I preordered the iPhone 6 16GB which has always been enough for me but I am rethinking things and might want to go with 64. The att gold model I want is still available for 9/19 delivery. What's the best route to go if I decide to switch sizes. Call apple and maybe they can just edit my existing order or just cancel and reorder? I just want to be sure I still get it on release day. Idk if someone has done this yet. Thanks