Find "Call forwarding"
Press Applications.

Press Settings.

Press Call settings.

Press Voice call.

Press Call forwarding.

Deactivate all diverts
After a moment the current settings are displayed.

Press one of the following options:
Always forward
Always forward

Forward when busy

Forward when unanswer

Forward when unreachab

Press Disable.
The request is sent.
Repeat until all diverts have been deactivated.
The request is sent.
Repeat until all diverts have been deactivated.

Exit
Press the Home key to return to standby mode.
