Getting an upgrade on my iPhone

Unless I’m mistaken, all “upgrade” means these days is that your current phone is paid off and you can get a new phone with the same number.  I don’t think there is any discount associated with an upgrade anymore.  You can go the the Apple Store just like you go to an AT&T store.  You can choose a phone locked to AT&T, with a SIM with your number, and service from AT&T, same as you would get if you went to an AT&T store.  Or you can buy an unlocked phone that comes without a SIM, and then you simply get a replacement SIM from AT&T and put it in the new phone.  If you’re getting an iPhone 14, it’s only eSIM, so you’d have to convert your physical SIM to eSIM, if that’s what you have, but that isn’t hard.

Thank you! I will go to the Apple store. AT&T was useless in giving an answer to this question.