As far as I understand the "external_id" represent the "User id" we see in a user's or lead's profile.
Is it possible to change a contact's "external_id" with a "PUT /contacts/<id>"?
I tried but it doesn't seem to work. I can change other properties like "email" just fine, but "external_id" doesn't change in the contact model in the response to the call, despite the status code being "200 OK".
Is there any other way to change the "user_id" of a contact otherwise?