It's actually very easy to add a day to your park passes. I just did this in November. All you have to do is while you are at your hotel, go down to the concierge desk & let them know what you want to do & they can do it for you right there. They just add it onto your room key. It was so easy. The best part was, it was really cheap! We had 3 4-day park hoppers & wanted to add another day & it was only $13 total for the 3 tickets! I was so excited that I even tried to convince my husband to stay a few more days (didn't work though) Have fun on your trip!