Find "Change SIM PIN"
Slide your finger down the display starting from the top edge of your phone.
Press the settings icon.
Press the settings icon.
Press Security.
Press Set up SIM card lock.
Press Change SIM PIN.
Change PIN
Key in your current PIN and press OK.
Key in a new four-digit PIN and press OK.
Key in the new PIN again and press OK.
Return to the home screen
Press the Home key to return to the home screen.