iPhone 13 Pro Max How do I upgrade from iPhone 13 Pro to iPhone 13 Pro Max within 14 day window if I got device through Carrier contract (AT&T)

[hasanahmad]

If I got it for 36 months through AT&T, how do I "upgrade" to a Pro Max. can I do it in store at ATT? can I do it in an Apple store? do I need to do it online?

 

[mateo124]

I’m considering swapping my 256GB 13PM for a 512GB once it arrives. If it’s a corporate store and not an authorized retailer, I think as long as it’s unopened they’ll exchange it for you without much issue.