Hi, I got the 6s+ and gave my relative a 5s to upgrade her from 4s. What is the easiest way to upgrade to 5s? I upgraded her from 4>4s last time and I think we may have just called A&TT and swapped SIM cards IIRC. Since 5s has different SIM what is the easiest way to proceed? She is on a family plan and I am on unlimited. Thanks.