curl --request PATCH \
  --url https://prod.featherhq.com/api/v1/threads/{threadId}/close \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "reason": "<string>"
}
'

{
  "thread": {
    "id": "<string>",
    "organizationId": "<string>",
    "agentVersionId": "<string>",
    "toPhoneNumber": "<string>",
    "fromPhoneNumber": "<string>",
    "fromPhoneNumberId": "<string>",
    "leadId": "<string>",
    "isActive": true,
    "createdAt": "<string>",
    "updatedAt": "<string>",
    "closedAt": "<string>",
    "closedReason": "<string>",
    "metadata": {},
    "variables": {}
  }
}