Changing to unlocked phone

[dragons1]

I've had my go-phone(ZTE F-160) 6 plus months now and im getting ready to purchase an unlocked gsm phone do i just take sim out of my phone and put in new phone and it works or do i call att customer service for help

[efparri]

One can change GSM phones unilaterally.

[johnhere]

It should work unless the sim is locked to the phone. If it doesn't a quick call to cs should fix it.