You need to meet these two condition
1. In contract with att over 6 month
2. Optain an non-att sim card
call att, **don't dial 611! Call the 1800 number on a landline**, get to tech support. Tell them you are going out of state and you want them to unlock the phone cause they charge too much.
You insert the non-att sim card machine ask you to enter code.
Rep give you a code, done!
By doing this won't effect warranty with htc.
