Forward calls to your voice mailbox or another phone number
If you cannot answer your calls, you can forward incoming calls.
Select 
> Settings and Calling > Call divert > Voice calls .
Select If not answered > Activate > To voice mailbox .
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
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Select All voice calls > Activate > To other number .
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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.