To do that requires you to first modify the reservation you have to remove two days, and then make a new reservation for those two days at the second resort. There can be a risk that between the time you do the modification to making the new separate reservation, the room at the second resort you want could fill via others making reservations. You could also thereafter find that those two days are no longer available in relation to your first resort and thus you cannot get hem back. As a result if one is considering doing a split stay, it is best to make two separate reservations at your home resort 11-months out, one of which is for the time you want to switch. Then, at 7 months out you need only modify one of the reservations and cannot lose it while attempting the modification, meaning if the other resort reservation turns out not to be available, you can just have MS combined the two home resort reservations after 7-months out.