Mixed up 6+ order and phone numbers with ATT NEXT

So i ordered 2 phones one black one silver. Unfortunately in my haste I upgraded with the wrong numbers. My number is supposed to be the silver phone and my friends number is supposed to be on the black phone.

How can we switch these around? calling apple? or att? i dont want to cancel and re do it.

because one phone is for 12 month plan and the other 18 month. i dont know if its just as easy as swapping SIMs.

 

yea but what if one phone is on NEXT 12 and the other on NEXT 18? isnt that going to screw up the monthly pay schedules? and future upgrade?

or swapping sims going to automatically tell ATT which one is for what plan type?