Please help me understand unlocking

[TeaganRoy]

I have two ATT iphones and we are switching to Verizon because my company offers a discount there. I am buying new phones from Verizon, but I want to hang onto our older iphones from ATT in case a new one breaks/gets lost/etc. I have done the online unlock request thru ATT, confirmed the request, and got the email that the request to unlock was approved. The rest of the email tells me to take out my old SIM card and put a new one in. Is it necessary that I do that with the SIM card Verizon is going to be sending me with the new phones, or can I transfer the SIM card later if something with the new phones goes wrong? And at this point could I sell the old phones on ebay as an unlocked device, or would I have to list it as an ATT phone?

 

[C DM]

You can do it later if you want, or not do it at all. The phones are unlocked per AT&T, so that's basically that.

 

[jetsam]

If the unlock was properly processed by AT&T, then there is no need for you to do anything at this point. However, if it were me, I'd want to test the phone with a non-AT&T SIM, just to be sure the phone is really unlocked. 99.99% of the time, the unlock goes properly. Nevertheless...