Steps to take before upgrading my phone?

[Rockadile]

I can now swap my 6 for the 6S through AT&T Next.
I've read awhile ago to turn off Find my iPhone and delete/reset the whole phone.
Do I need to bring in charger or box?
Anything else?

 

[Newtons Apple]

I would call them. I do not think they want the charger back and sure they do not want the headphones back. Just the phone. Make sure you do a hard and encrypted backup via iTunes before resetting your phone. I would also back it up on the cloud just in case.

 

[willmtaylor]

I would do what was mentioned above. Also, don't disable Find My iPhone and reset the phone until you get to the store.