ATT Device Unlock Review
Here is showing a couple of steps on how to unlock Samsung Galaxy s6, and use it overseas or worldwide with AT&T device.
Go To Att Com Deviceunlock
Unlock Your AT&T Phone For Free - AT&T Unlock Portal
Unlock your phone for free and I will show you how to unlock an Android phone on AT&T. The first thing you need to do is to get the IMEI number of the phone, and how you get it?