If you cannot answer your calls, you can forward incoming calls.
Select > Settings and Calling > Call divert > Voice calls.
|Forward voice calls when unanswered|
Select If not answered > Activate > To voice mailbox.
|Forward voice calls when you are currently in a call|
Select If busy > Activate > To voice mailbox.
More than one forwarding option can be used at the same time.
Forward all voice calls to another phone number
Select All voice calls > Activate > To other number.
Type in the number. To use a number saved in your contacts list, select Find.
Call barring and call forwarding cannot be used at the same time.