I am going to redo this post as the last one was very confusing. Ok since you are all talking about adding a new line and upgrading one of yours.. or even if you are going to add lines to do BOGO if it happens. This next process is the proper way to do it to avoid problems

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Go get the new BOGO phones. After, whether it be the same day or next or whenever, put the new BB's on the lines you want them on(i.e.-555-555-5550 is your existing line, you add 555-555-5551. Take the BB you added on the 5551 and put it on the 5550), then activate another old phone on the new line(i.e.-take a phone that doesn't require data and activate it on the new 5551 line). After that basically wait til you get your first months bill for the new line to cancel. reason being- when you add a line there is a 30 day worry free guarantee which waives the ETF... but you have to send the phone back if you do that. So wait until after that then cancel the new line pay the ETF and voila. does this make better sense?