Find "Fixed Dialing Numbers"
Slide your finger down the display starting from the top edge of your phone.
Press the settings icon.
Press the settings icon.
Press SETTINGS.
Press Call.
Press Fixed Dialing Numbers.
Turn fixed dialling on or off
Press Enable FDN or Disable FDN (depending on the current setting).
Key in your PIN2 and press OK.
Return to the home screen
Press the Home key several times to return to the home screen.