How to unlock an iPhone 5 on AT&T for tmobile?

How to unlock an iPhone 5 on AT&T for tmobile?

There are two ways:
Free Method - visit official AT&T website and request the IMEI unlock by using submission menu. Wait from 24 hours to 1 week and if you are lucky your device will be unlocked
Paid Method - you can order AT&T unlocking as they are usually the cheapest prices. Personally I used the service (watch my source) as they got only positive feedbacks. Then you device will be unlocked under 24 hours so you'll be able to use it for T-Mobile network