Where did you get this done? I am in the US. I called a few AT&T stores about this and some said they would do it, and others said told me to contact a corporate store. I explained to them that I used my eligible upgrade in November, and I want to cross upgrade using a different line under the same plan that is eligible for an upgrade. My line would be a smartphone line but the line's upgrade I would be using would still be a basic phone line. I told them that I understand the iPhone uses a different sim card and I asked if I would be able to use the upgrade for me, and keep the line whose upgrade I would be using to remain a basic phone with a regular sim card. I was told that BOTH lines would have to have a data plan - and this does not seem right. Why would the basic phone line need a data plan to do a cross upgrade? How do I know if the AT&T store is a corporate store or not?
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Why would I need to put a data plan on the upgraded line if it would remain a basic phone line? I would just want to use the upgrade for the line for myself to get a smartphone (which I know I would need a data plan for), not upgrade the phone basic phone itself.