Hi, This phone says that it can hold two sim cards, and also that it has expandable storage. from what I can see from Samsung it looks like it is a choice of one or the other (ie either you can put two sim cards in, or you can put one sim card in and one sd card, but the tray is only capable of having one or the other from the beginning. So my question is, can you decide to have two sim cards or one sim card and one sd card in the same phone? Thank you