---
title: "Update Phone Number"
method: PATCH
path: "/agents/phone-numbers/{id}"
tags: ["Phone Numbers"]
---

# Update Phone Number

`PATCH /agents/phone-numbers/{id}`

Update a phone number's label, agent assignment, or provider

## Path parameters

- `id` string, required

## Headers

- `Cartesia-Version` '2026-03-01', date, required

## Request body

- UpdatePhoneNumberBody — Fields to update on a phone number. All fields are optional. Set `agent_id` to `null` to unassign the current agent.
  - `label` string — A new human-readable name.
  - `agent_id` string, nullable — Assign an agent to answer inbound calls to this number, or `null` to unassign.
  - `provider` object — Change the provider. Pass `{ "id": "..." }` to reference an existing provider. The phone number must exist in the target provider's Twilio account.
    - `id` string, required

## Response `200`

Phone number updated.

- PhoneNumberResponse — Common phone number fields.
  - `id` string, required — Unique identifier for the phone number.
  - `label` string, nullable — A human-readable name for the phone number.
  - `number` string, required — The phone number in E.164 format (e.g. +14155551234).
  - `agent` object, nullable, required — The agent that answers inbound calls to this number, or `null` if unassigned
    - `id` string, required
    - `name` string, required
  - `created_at` string, date-time, required — UTC timestamp when the phone number was created.
  - `updated_at` string, date-time, required — UTC timestamp when the phone number was last updated.
  - `provider` union, required — The telephony provider associated with a phone number. One of `Twilio` or `Cartesia`, determined by the `type` field.
    - TwilioProviderResponse — A linked Twilio account. The `api_key_sid` field is partially masked in responses.
      - `type` 'twilio', required — Always `"twilio"`.
      - `id` string, required — Unique identifier for the provider.
      - `account_sid` string, required — The Twilio account SID.
      - `api_key_sid` string, required — The Twilio API key SID (partially masked).
      - `region` 'us1' | 'ie1' | 'au1', required — The Twilio region the phone number and API key are configured for. `us1` (US), `ie1` (Ireland), `au1` (Australia). Default is `us1`.
    - CartesiaProviderResponse — A Cartesia-managed provider. US phone numbers only.
      - `type` 'cartesia', required — Always `"cartesia"`.

## Other responses

- `400` — Update failed. Possible reasons: phone number not found in the target provider account, or webhook configuration failed.
- `404` — Phone number, agent, or provider not found.

---

[API](https://skmtc.net/cartesia/apis/cartesia-api.md) · [All operations](https://skmtc.net/cartesia/apis/cartesia-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/cartesia/cartesia-api/revisions/8910812440d3/schema)