If a customer wishes to transfer the account to another person and have nothing further to do with the unit, it is best to start a new subscription with the correct customer details. When creating the new subscription chose the 'move in' date as the next billing date to keep the billing schedule in line.

If an account just needs the contact person updated, but the main details like payment method, address etc are staying the same, you can do this by editing the contact details on the customer page. This is most likely useful when dealing with business customers if their contact changes.