I upgraded to the 3G-s on Friday but I have a Genius Bar appointment for my old 3G tomorrow to address some issues and hopefully have it replaced due to the infamous cracks in the plastic casing. Do I need to put my SIM card back in the old 3G phone prior to the appointment? Will I need to reactivate it in iTunes or can I just swap the SIM right before the appointment? And, will reactivating the old phone cause problems with my newly extended AT&T contract on the 3G-s? Thanks for any advice you might have!