We'll be there the week between Christmas and New Years and realize it will be super busy. Our original plan was to buy 3-day 1 park tickets and spend two days at IOA and one at Universal. Now we're rethinking whether we want to go full-speed for three days or maybe only do two days and have some time to relax. So if we buy the 2-day 1 park tickets and decide we need a third, can we add on that third day before we leave the park, or would we have to buy a separate 1-day ticket?