I have an awfully specific question that I am hoping someone has already had some experience answering: I have several lines on my AT&T account--including an iPhone and a Blackberry. I am the Blackberry user. In order to upgrade to the iPhone4, I used the upgrade eligibility from the existing iPhone line. AT&T has informed me that I will need to switch the EMEI #'s so that the new iPhone4 works correctly with the correct phone number. My question is then: Do I plug my iPhone4 into my computer and attempt to activate the phone prior to calling AT&T to switch the EMEI #'s? An AT&T rep seemed to think I should activate through iTunes first before calling AT&T to complete the switch. My concern is that the existing iPhone will be out of service for some time while I complete the switch or activate the phone (I'd like to at least be prepared for that if it is the case). Any thoughts? Appreciate the help!