And, the challenge to booking and then switching at 11 months is that you'll need to have enough points for both reservations simultaneously, unless you cancel your first reservation to book the second reservation (which you might not get because everyone is online when reservations open at 7 months to do exactly what you're doing, and there's a chance your original reservation won't be re-bookable). There is a thread somewhere on how to do a 2 browser delete/book, but I've never done it, and the information may not be accurate any longer.