Depending on when you will arrive, it might be worthwhile keeping the reservation and you will have a room waiting for you whenever you arrive. If you will not arrive until after 4pm on the 2nd day, I would cancel (if you are doing that within 30 days of arrival the points will be in Holding status).
Otherwise, just call the resort and let them know you will be arriving a day late. They will NOT cancel your reservation and our room will be waiting whenever you arrive. Late arrivals are not a problem at all, but I;d still call to let the resort know you'll be late.
Good luck!