curl --request DELETE \
  --url https://api.topyappers.com/api/v2/crm/lists/{list_id}/creators/{user_id} \
  --header 'x-ty-api-key: <api-key>'

{
  "message": "OK",
  "response": {
    "list_id": "<string>",
    "user_id": "<string>",
    "removed": true
  }
}