network
How do I unlock my phone to ue on a new network/carrier.
My father got me his old iphone but it is on a different provider to what i'm on
iPhone 5
You need to contact the carrier that it's currently locked to and see what you have to do to file what's known as an "unlock request". After they get it unlocked on their end all you have to do is restore the device as new.
This article may help you out: http://support.apple.com/kb/HT5014