I want to take advantage of the trade in offer ($200), however do I have to do this on the website or can i go into a store to preorder? If i proceed with online how will i get the $200 promotional trade in vaule? Also I have 3 active lines, and 2 out of the 3 lines want to use this. Is this allowed, or is it one line per acocunt? Does our plan change as well, or does it stay the same?