Find "Lock code"
Press the Menu key.
Press Settings.
Press Phone.
Press Phone management.
Press Security settings.
Press Phone and SIM card.
Press Lock code.
Change phone lock code
If a phone lock code has been created already:
Key in the current phone lock code and press OK.
Key in the current phone lock code and press OK.
The first time you use the phone lock code, key in a code of your own choice.
Key in a new phone lock code and press OK.
The first time you use the phone lock code, key in a code of your own choice.
Key in the new phone lock code again and press OK.
The first time you use the phone lock code, key in a code of your own choice.
Exit
Press the Menu key to return to standby mode.