A relative asked me if this is possible and I think it is, but I'd like to know for sure. They have a family account with 2 dumb phones and are eligible for upgrade. They would like to get 2 iPhones with their upgrade eligibility, but they would like to stick with their dumb phones. Instead they would give their iPhones to their kids. If they purchase the iPhones, can they go back to the dumb phones and avoid to pay the monthly data plan?