PATCH /api/v2/interactions/{id} for queue transfer fails with 400

Trying to transfer an active voice call to a different queue programmatically. I’m sending a PATCH request to /api/v2/interactions/{id} with the target queue ID in the to object. The response is a 400 Bad Request saying the action isn’t valid for the current state.

{
 "to": [{
 "id": "queue-uuid-here",
 "type": "queue"
 }]
}

Is there a specific action field I need to set, or is the interaction state wrong?