The following steps are intended for the HTC EVO 3D running any Android software.
Tap the Phone App.
Dial ## MSL #
(Note: The MSL will be found in your activation email or can be found in your online account under Programming Instructions.)
Tap Edit Mode
Tap Mobile Directory Number(MDN)
Tap near the end of the number and delete. Then enter the new MDN. Tap OK when finished.
(Note: The MDN will be found in your activation email or can be found in your online account under Programming Instructions.)
Tap MSID
Tap near the end of the number and delete. Then enter the new MSID. Tap OK when finished.
(Note: The MSID will be found in your activation email or can be found in your online account under Programming Instructions.)
Tap Menu
Tap Commit Modifications
The phone will now restart and then the phone will be ready for use.