Ok so I am switching from AT&T to Verizon and I am considering the Galaxy S3, and the new iPhone. I know the new iPhone is basically guaranteed to be available for preorder Sept. 12th.. I've always been an iOS user and am currently using an iPhone 4S. I've used a Nexus 7 but never really used an Android phone. My question is, if I get an S3 tomorrow (signing new 2 year contract) and I decide on the 12th that I actually do think I'll prefer the iPhone, what is Verizon's policy on doing an exchange like this?