This is managed via Groups, which determine which Users are permitted to use which numbers.
The Sender should be considered a 'fixed point'. To 'transfer' the number, update the Users aligned to the Sender via its Group. For simplicity, we recommend preserving the existing Group.
- Add the profile of the new user to the Group that contains the desired Sender
- Remove the profile of the old user (optional)
- Change the name of the Group (if necessary)