My advice would be to upgrade via My Verizon. This is how I do it. If your wife's line is eligible and yours is not simply log into My Verizon and transfer your wife's upgrade to your line and then begin the upgrade process. This beats going into a store in so many ways. You do all the work and there is no rep to guilt you about the process being too difficult or blah, blah, blah. The problem with upgrading your wife's line and THEN switching ESNs is once you program your wife's phone the Sim card is locked to her line. Maybe the rep in store would have you sign the contract and never activate your wife's line on the iphone and simply do an ESN change. Who knows? It's too iffy. Your best bet is to cut out the middle man and do it yourself. Did the Gsmith guy say they would CHARGE you for the ESN change? Seriously? Screw that. Do it yourself. You'll feel much better. So will your wallet.