How do I unlock an AT&T Passport for use on T-Mobile?

I recently sold my AT&T version Passport (with the curved edges) on eBay, as I've upgraded to a Priv.

After shipping the item, the buyer messaged me to ask if it was unlocked. It turns out she wants to use it on T-Mobile.

How do I figure out if it is unlocked, or to unlock it for her? She has the phone, but I want to help resolve the issue for her so I don't wind up with negative feedback. Is an AT&T Passport unlockable? I'm really not at all familiar with the process, or if anything is even required to make it work on T-Mobile.

Any guidance would be appreciated.

In system settings go to Network and connections..go to Mobile Network...go to Sim Card settings.

It will list if device is unlocked or not in the Network subset and Service provider area.

Don't know if ATT is compatible with T-Mobile but there is a thread somewhere which does discuss that....cant remember exact title though.

Posted via CB10

This might help until someone with a lot more knowledge jumps in.
http://forums.crackberry.com/showthread.php?t=961279

Posted via CB10

How to figure out if it's unlocked or not: if you bought the phone from AT&T and don't remember unlocking it, it's locked. That's usually how AT&T-sold phones are for first buyers.

The phone is definitely unlockable, and there are a few ways to go about unlocking it.

The cheapest way--if the phone is paid off at AT&T and meets certain other criteria--would be to request the unlock code from AT&T. You can do so at: att.com/deviceunlock

Otherwise, you can contact a third party unlocking service and they'll do it most likely for a fee.

It might also be a good idea to send the eBay buyer a link to these instructions: http://forums.crackberry.com/blackbe...ctions-961531/

Raino is 100% correct

if you don't remember unlocking it yourself then it is LOCKED 100%

You can contact AT&T to request the code, try a few times if they don't agree the first time.

If you still can't get it we can help you.

Also you can view this video here showing how to unlock an AT&T Passport it is very easy

https://youtu.be/6DUR6vb4j7E