Hi there and welcome
To deregister, press the menu button then #131
All handsets registered to the base unit are displayed.
Select the Handset you want to deregister, then yes and you will hear a confirmation tone
If you have any problems, or would like any additional information or assistance, please do not hesitate to let me know.
Else if you can take a second to rate my service by clicking one of the stars at the top of the screen then submit, that would be greatly appreciated.
its the handset you are dregistering
ok, to register a new phone, follow the instructions on page 28 of the manual here
i will forward this to customer service.