Vodafone 550
Find " Change barring pass..."
Press the menu icon.
Press Settings.
Press Call settings.
Press Call barring.
Press Change barring pass....
Change barring password
Key in the current barring password (default is 1919) and press OK.
Key in the required barring password and press OK.
Key in the barring password again and press OK.
Exit
Press Disconnect to return to standby mode.