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Update handoff destinations, add new transfer points, and manage SIP routing – all without taking the agent offline. Test changes safely in Sandbox before promoting to Live.

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Quick reference

This page covers the UI-based Call Handoff feature. Ask if your project uses the code-level transfer_call function.

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Edit an existing destination

overview
  1. Go to Voice > Handoffs.
  2. Hover over the destination you want and click Edit.
  3. Change the Number / SIP URI or Description.
  4. Save.
  5. Make a quick test call in Sandbox and confirm the transfer works, then promote your version.
Common use cases:

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Add a new handoff destination

  1. Click Add handoff.
  2. Fill in:
    • Name – e.g. “VIP host desk”.
    • Method – leave SIP REFER unless your telephony team says otherwise.
    • Route / Number – +1XXXXXXXXXX or a SIP URI.
    • (Optional) SIP headers if your PBX needs extra context (see next section).
  3. Add → test → promote.

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Add SIP headers (optional)

SIP headers let you pass metadata – account ID, language, VIP flag, etc.
  1. While creating or editing a destination, click Add SIP header.
  2. Enter a header name (custom headers start with X-).
  3. Enter a value, or use a variable such as $caller_id.
  4. Save.

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Using your own Twilio number

If you bring your own Twilio DID:
  1. Connect Twilio under Voice > Numbers > Twilio (enter Account SID + Auth Token).
  2. In Twilio, point the number’s Voice webhook at your agent URL.
  3. Back in Voice > Handoffs, use that number as the Route field.
US numbers need A2P 10DLC registration for SMS.

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Test before you ship

  1. Call the Sandbox number.
  2. Trigger the scenario that should transfer.
  3. Confirm the call operates how you are expecting.
  4. Promote the new version to Live.
If the transfer fails, double-check:
  • Number format (+ and country code)
  • Firewalls or other rules on the destination side
  • SIP header spelling

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Common workflows

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Updating after-hours routing

  1. Identify which handoff destination handles after-hours
  2. Update the phone number or SIP URI
  3. Test in Sandbox during and after business hours
  4. Publish and promote to Live
Time: 10-15 minutes

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Adding a new department handoff

  1. Get the phone number or SIP URI from the department
  2. Add new handoff destination with clear name
  3. Update FAQs to reference the new handoff
  4. Test the full flow in Sandbox
  5. Publish and promote
Time: 20-30 minutes

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When to escalate

  • You need more conditional logic than the UI can express
  • The destination uses a non-standard SIP method
  • You are seeing 4XX/5XX SIP errors
Last modified on July 10, 2026