Planning to use my early upgrade (AT&T) to get the 5S for my gf. When the phone arrives is it already tied to my line? I could've sworn last year when the 5 came, I turned it on and was able to just activate without even calling AT&T
Just call ATT before turning on the iPhone and let them know the situation. They will guide you through it. I'm pretty sure they just make a note in their system and you put your GF's sim card into the new 5s.