I'm doing this for the first time so excuse my ignorance ...so how does this work: - I got a 7+ 32 last saturday, it works beautifully. - after re-thinking about it, I figured 128 would be better. - I just reserved a 256 at the same store (there was no 128 so I thought what the hell ) - I'm still in my 14 days period ....Do I just need to bring my current 7+ and exchange for the new one? What about the price difference, is it going to be adjusted on my next bill? Again, sorry for being clueless on the matter. 7+ are in short supply and I was lucky to find one this morning, I don't want to mess that up!