# states on PATCH /update-retell-llm/{} stops working

Calls to PATCH /update-retell-llm/{}, body parameter states on Retell AI API stop working on February 1, 2027.

- API: Retell AI API (api.retellai.com)
- Kind: Endpoint removal
- Takes effect: February 1, 2027
- Calls after that day: fail
- Calls it hits: `PATCH /update-retell-llm/{}`, `body parameter states`
- Source: [Announcement](https://docs.retellai.com/deprecation-notice/2026/12-15_multi_prompt_agents)
- Page: https://www.okapi.bot/providers/retell-ai-api/breaking-changes/states-on-patch-update-retell-llm-stops-working/

## What to use instead

Edit the agent as a conversation flow with PATCH /update-conversation-flow/{conversation_flow_id} instead.

Multi-prompt agents have no direct API equivalent: rebuilding one as a conversation flow changes how it handles calls and needs testing.

## Retell AI API's words

> Retell is retiring multi-prompt agents in favor of conversation flow. New multi-prompt creation ends on 12/15/2026, and editing ends on 02/01/2027.