Ability to remove coaches from contacts in CCM via the API

The ability to remove coaches from a contact for a client would be very beneficial and prevent any issues with needing to do this manually, which is the only current way to remove a coach.

If this is not possible, perhaps a special value can be passed into secondary coach field, such as ‘DeleteCoach’ or 'RemoveCoach', this could serve to be a way to delete the coaches via the API, and avoid the issue with unintentionally deleting a coach from providing an empty string.