> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tracklysms.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Update Number Registration

> Revise an unpublished delegated registration draft with concurrency protection.

Use the same API-audience registration authority and request binding as [creation](/api-reference/v2/agent-number-requests/create). Send a JSON object of at most 64 KiB containing `revision` and at least one registration field to change. Unknown or duplicate fields and query overrides are rejected.

<ParamField path="request_id" type="string" required>
  The request ID returned by creation.
</ParamField>

<ParamField header="Idempotency-Key" type="string" required>
  1–255 printable ASCII characters; retain the key and exact body for this operation.
</ParamField>

<ParamField body="revision" type="integer" required>
  The current positive revision from [readback](/api-reference/v2/agent-number-requests/get).
</ParamField>

Returns `200` with `{"request": ...}`. Use the returned revision for subsequent work. A changed draft needs a preview and review of its new content; agents cannot edit published drafts.

After a `409` revision/idempotency conflict or uncertain response, read the same request and reconcile before another mutation. Errors also include `400` invalid input, `401` invalid bearer, `403` missing authority, `404` binding mismatch, `413` oversized body, `422` unsupported details, `429` rate limit, and `503` unavailable dependencies/indexes. No update authorizes publication, DNS changes, or paid submission.