Change the PIN code of your SIM card using a short code or via your mobile phone menu. For your security, avoid using obvious PIN codes such as 1111 or 1234.
Type in the short code **04*Old PIN code*New PIN code*New PIN code# on your mobile phone and press the call key. Instead of Old PIN code, enter your current PIN code and instead of New PIN code, enter your new 4-digit PIN code. For example: **04*1234*1369*1369#
Go to Settings > Security > SIM card lock > Change PIN code. Enter your old PIN code first and then enter a new code of your choice. If your mobile phone has a different menu, please consult the manual of your device or the manufacturer’s website.
Did you forget your PIN code? When you've entered the wrong PIN code three times, your PUK code will be requested. Afterwards you can choose a new PIN code.