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Introduction

Warm Transfer changes how your AI hands off to a human. Instead of an immediate transfer, the AI starts a second call to brief your human agent on the call details. Once the agent is ready, the calls merge into a smooth three-way conversation where the AI introduces everyone and then steps back.

Intelligent Handoffs

AI briefs human agents before connecting customers, ensuring agents understand the context and customer needs

Seamless Merging

Professional call transitions with announcements and hold music for smooth customer experience

Multi-Agent Fallback

Try multiple agents until someone’s available, with smart tracking of each attempt

Advanced Controls

IVR navigation, live translation, timeout management, and voicemail handling
Enterprise Feature Required: Warm Transfer requires an enterprise account due to its advanced call routing and management capabilities. Contact our team to learn about our plans.

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How Warm Transfer Works

Understanding the warm transfer flow helps you configure it effectively:
  1. Customer Requests Transfer: During a call, your AI determines a human agent is needed
  2. Proxy Agent Call: AI calls the human agent using your configured phone number and settings
  3. Agent Briefing: AI explains the customer situation to the human agent using your briefing prompt
  4. Agent Preparation: Optional - human agent can ask questions or prepare before taking the call
  5. Call Merging: Both calls merge together with hold music ending for the customer
  6. Professional Handoff: AI announces the introduction and steps back from the conversation
  7. Pure Human Conversation: Customer and agent continue without AI involvement
If agents don’t answer or are unavailable, the system can try multiple agents in sequence or fall back to voicemail handling.

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Configuration Interface

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Enable Warm Transfer

When you enable warm transfer on a Transfer Call node, you’re switching from a basic “cold transfer” (where the customer gets transferred directly) to an intelligent handoff system. The AI will manage the entire transition process, ensuring human agents are prepared and customers experience a smooth transition. Location: Transfer Call node → Toggle “Enable Warm Transfer”
Default: Disabled (uses standard transfer)
Impact: Unlocks all warm transfer configuration options below

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Core Configuration Options

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1. Live Translation

What it does: Provides real-time language translation during the merged call between customer and human agent. Learn more about Live Translation in our changelog. Why it matters: Perfect for international support where your agents speak English but customers speak other languages. Both parties can communicate naturally in their preferred language. How it works: During the merged call, both the customer and agent hear the original speech plus a translated overlay. The agent hears everything in English, while the customer hears the agent’s responses translated into their language. Configuration:
  • Default: Disabled
  • Impact: Changes the entire call merging process to use translation bridges instead of standard conferences

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2. Proxy Agent Number

What it does: Controls which phone number appears when your AI calls the human agent. Why it matters: Human agents often screen calls or have different behavior based on caller ID. Using a familiar number helps ensure your agents will answer the proxy call. How it works: This is the first step of warm transfer - your AI needs to call the human agent to brief them before bringing in the customer, and this setting determines what caller ID they see. Configuration:
  • Format Required: E.164 format (+1234567890)
  • Default: Automatically selects from your available outbound numbers
During a warm transfer, Bland keeps the Twilio account authorization from the original call. So if you want to use a custom proxy agent number, it needs to come from that same Twilio account.

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3. DTMF Sequence

What it does: Automatically “presses buttons” on the phone system after the proxy agent call connects. Why it matters: Your human agent might work at a company with an extension system or require PIN entry. This automates the navigation so the AI can reach the specific agent without manual intervention. How it works: Use w for half-second pauses, then add the digits to dial. The system waits for the call to connect, then automatically sends the specified button presses. Examples:
  • Extension 54: w54
  • External line then extension: w9w123
  • PIN required: ww1234#
Configuration:
  • Example: w54 (pause, then dial extension 54)

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4. Live Agent Briefing Prompt

What it does: Controls what your AI says to the human agent when it calls to brief them about the customer. Why it matters: This is the AI’s chance to quickly explain who’s on hold and what they need, ensuring the agent is prepared and can provide better service from the moment they take over. How it works: Two modes available - Dynamic (AI creates personalized briefings based on instructions) or Static (AI says exactly what you write). You can include variables like {{customer_name}} or {{issue_description}} for context. Configuration: 
Background Information: 
You have just connected to a live support contact. Your purpose is to provide them information on a call you just previously got off of.

Tasks:
- Introduce who you are to the live agent
- Provide a quick overview of the call summary to the live agent you are connected with. The short summary should be one or two sentences maximum, and should include key details like the patient's name, and why they want to be transferred.

For context, below is the formal call summary: 
{{call_summary}}

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5. Allow Live Agent Conversation

What it does: Gives the human agent control over when the calls get merged together. Why it matters: Sometimes agents need a moment to pull up customer records, ask clarifying questions about the situation, or simply mentally prepare before taking over the conversation. How it works: Default flow is automatic merging (AI briefs agent → calls automatically merge → everyone talks together). When enabled, the agent controls timing (AI briefs agent → agent can ask questions or prepare → agent tells AI when ready → calls merge). Configuration:
  • Default: Disabled (automatic merge)
  • Effect: Adds merge control tools to the proxy agent
  • Prompting: When this is enabled, make sure your live agent briefing prompt clearly lays out when the agent should use the “merge” tool. That way, your agent knows exactly when to bring the calls together.

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6. Hold Music

What it does: Plays pleasant background music for the customer while the AI is briefing the human agent. Why it matters: Instead of dead silence or “please hold” messages, customers hear professional hold music while the AI is talking to the agent. This keeps the experience polished and pleasant. How it works: Choose from seven built-in classical music options or upload a custom URL. The music plays automatically when the customer is placed on hold during the agent briefing phase. Configuration:
  • Options: 7 built-in classical options or custom URL
  • Custom URL: For branded hold music
  • Preview: Built-in audio preview for testing

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7. Merge Call Prompt

What it does: Controls what gets announced to both the customer and agent when the calls are merged together. Why it matters: This announcement helps set the tone for the human conversation and makes sure both parties know what’s happening during the handoff. How it works: Two approaches available - Dynamic (write a prompt that tells the AI how to introduce the agent to the customer) or Static (AI says exactly what you specify, word-for-word). The AI introduces the agent to the customer and steps back from the conversation. Configuration:
  • Context: Dynamic mode receives full conversation transcript for personalized handoffs
Background Information:
You are about to merge two calls together - the customer and a live support agent. Your purpose is to professionally introduce them to each other and then step back from the conversation.

Tasks:
- Greet the customer by name if available
- Let them know their support specialist is joining the call
- Briefly mention that the agent has been briefed on their situation
- Step back gracefully from the conversation

Keep it warm, professional, and concise. Use any relevant context from the conversation summary below:
{{call_summary}}

Perfect! I now have one of our specialists joining the call. They've been briefed on your situation and will help you from here. Thank you for your patience, and I'll let you both take it from here.

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8. Optimize for IVR/Queue Systems

What it does: Configures the proxy agent to better handle phone systems, voicemail, and hold queues. Why it matters: Many businesses have complex phone systems. Regular call settings might cause the AI to hang up when it hits voicemail or gets stuck in a queue, preventing successful agent connection. How it works: Makes the proxy agent more patient and persistent, designed to navigate phone trees and wait in queues until it reaches a human. Enables answering machine detection, activates wait-for-greeting mode, blocks interruptions, and extends patience for queue systems. Configuration:
  • Default: Enabled
  • Impact: Agent uses specialized tools designed for phone system navigation

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9. Hold Timeout

What it does: Sets a maximum time limit for how long the system will try to reach human agents. Why it matters: Sometimes agents don’t answer, or they’re stuck in long queues. Rather than keep customers waiting indefinitely, you can set a reasonable timeout to maintain good customer experience. How it works: After the timeout expires, the system gives up on the transfer and moves to your configured voicemail handling. When IVR optimization is enabled, the timeout applies even if the call was “answered” but stuck in a queue system. Configuration:
  • Input: Time in seconds
  • Default: 1800 seconds (30 minutes)
  • Range: 30 seconds to 3600 seconds (1 hour)
  • Fallback: Triggers voicemail handling when exceeded

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10. Voicemail Message Configuration

What it does: Defines what happens when all attempts to reach human agents fail. Why it matters: Sometimes agents are all busy, don’t answer, or are unavailable. This configuration ensures customers still get a professional resolution instead of being left hanging. How it works: Two options available - End with message (play a polite explanation and end the call) or Continue in pathway (route the customer to another part of your conversation flow). When using pathway mode, you can visually see the connection in your pathway. Configuration:
  • Options: Message vs. pathway routing
  • Custom message: For message mode
  • Pathway routing: Target destination for pathway mode
  • Default Message: “I apologize, but our agents are currently unavailable. Please try calling back later or visit our website for additional support options.”

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Multi-Agent Fallback System

What it does: Tries multiple human agents in sequence until someone answers. Why it matters: Increases the likelihood of successful transfers by providing backup options when primary agents are unavailable, busy, or don’t answer. How it works: Enter multiple phone numbers separated by commas in the transfer number input field. The system calls the first number, and if no one answers or they’re busy, it automatically tries the next number, and so on. Each attempt is tracked independently for debugging. Configuration:
  • Format: Multiple phone numbers separated by commas (+1234567890,+1987654321,+1555123456)
  • Behavior: Tries each number in order until successful connection or all numbers exhausted, with the final attempt activating voicemail message configuration
  • Logging: Individual attempt results logged for debugging
Example Setup: 
+1555123456,+1555789012,+1555345678
This will try the first agent, then the second if the first doesn’t answer, then the third if the second is unavailable.

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Testing Your Configuration

Every warm transfer configuration includes a built-in testing panel where you can send a real proxy agent call to verify your settings work correctly. How to test:
  1. Click the “Test Proxy Agent” button in your Transfer Call node
  2. Enter a test phone number to receive the proxy agent call
  3. Answer the call and interact with the AI to verify your briefing prompt
  4. Test the merge process and handoff announcement
  5. Review the test results and logs
Safe testing: Uses special test mode that won’t affect your live call statistics or billing. Test scenarios to try:
  • Let the call go to voicemail to test voicemail handling
  • Don’t answer to test timeout behavior
  • Test DTMF sequences with your actual phone system
  • Verify hold music plays correctly
  • Test multi-agent fallback with multiple numbers

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Best Practices

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Agent Briefing Prompts

Keep it concise: Agents are busy - get to the point quickly with the most important information first. Use variables effectively: Include context like {{customer_name}} and {{issue_description}} from extracted conversation data to help agents prepare. Set expectations: Let agents know what the customer is expecting and what outcome they’re hoping for.

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Timeout Configuration

Balance patience with efficiency: 30-60 seconds for busy environments, 3-5 minutes for specialized support. Consider agent schedules: Set longer timeouts during known busy periods, shorter during staffed hours. Plan your fallback: Always have a helpful voicemail message or pathway continuation ready.

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Multi-Agent Setup

Order by availability: Put your most available agents first, specialists or managers last. Use different numbers: Include direct lines, mobile numbers, or numbers for different departments to maximize your chances of reaching an available agent. Test regularly: Agent numbers change, verify your fallback chain monthly.

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Troubleshooting

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Common Issues

Agents don’t answer the proxy call
  • Verify the proxy agent number is familiar to your agents
  • Check that agents aren’t screening unknown numbers
  • Test during known availability hours
  • Consider using a direct line instead of main number
Hold music doesn’t play
  • Check your custom hold music URL is publicly accessible
  • Verify the audio format is supported (MP3, WAV)
  • Test with built-in hold music first to isolate the issue
  • Ensure the URL uses HTTPS, not HTTP
Calls merge but agents can’t hear customers
  • This usually indicates a live translation configuration issue
  • Verify live translation is enabled/disabled as intended
  • Check that your account has translation permissions
  • Test without live translation first
Agent won’t merge the calls
  • Verify that the agent is prompted to use the “merge” tool in the briefing prompt if you have Allow Live Agent Conversation enabled
Proxy agent call is failing
  • Verify the proxy agent from number is from the same Twilio account as your parent call

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Debug Tools

Live Call Monitor: Watch warm transfers happen in real-time to identify issues. Test Mode: Use the built-in testing to safely debug configurations. Agent Feedback: Ask your agents about the quality of briefings and merge announcements. Call Logs: Every warm transfer attempt is logged with detailed information about each step. You can view them in the “Logs” tab of your Transfer Call node. The original call will be the first log entry, with a dropdown to view the proxy agent call.

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Getting Started

  1. Enable warm transfer on your Transfer Call node
  2. Test with a team member’s number using default settings, get a feel for the transfer process before customizing
  3. Write a simple briefing prompt
  4. Configure your setup based on test results
For additional support, reach out to your customer success representative, our support email, or Discord.