To change the mobile phone e-certificate PIN, you will need the current PIN. If you have lost the current PIN you will need have new e-certificates produced and choose a new PIN.
Here's how to set a new PIN for a Windows operation system:
1. Go to "Settings" and choose "Cellular + SIM"
2. Choose "SIM settings"
3. Choose "SIM applications"
4. Choose "Auðkenni"
5. Choose "Signature Settings"
6. Choose "Change ID-PIN"
7. Enter the current PIN and press OK
8. Enter a new PIN and press OK
9. Re-enter the new PIN and press OK