For MTN
Your default PIN is 0000.
To change your pin:
Dial: *777*Default Pin*New Pin*New Pin#
Example: *777*0000*1234*1234#
For 9mobile
Your default PIN is 0000.
To change your pin:
Dial: *247*Default Pin*New Pin# or *247*Old Pin*New Pin#
Example: *247*0000*1234#
For GLO
Your default PIN is 00000.
To change your pin:
Dial: *131*Default Pin*New Pin*New Pin#
Example: *131*0000*12345*12345#
For AIRTEL
Your default PIN is 0000.
To change your pin:
SMS: 'PIN Default-Pin New-Pin' to 432.
Example: Send "PIN 0000 1234" to 432 as SMS.