I switched from iPhone 5 to 6. I have AT&T. So after I move mu number from my old iPhone 5 to the 6, does this unlock the 5 automatically? If not, what's the best way to unlock it. Im looking to sell it. Thanks
No, it doesn't automatically unlock if you just switched to another phone.
If the old iphone 5 is still under a 2 year contract or next payments associated with it then it does not qualify for an unlock.
Contact AT&T for details.