I have 5 lines with Sprint, this black Friday they are offering the NV20 with a free 42" 4K LCD TV with the purchase of a new line. All 5 of my lines are off contract at the moment. I usually just do a 2 year upgrade for my phones. so here is my question. If i add a line to take advantage of the deal. after a week can i just close out one of my off contract lines and move the number over to the new line?