We have 7 day MYW w/PH tickets that we purchased a few years ago and have no expiration. We’re planning a trip this fall and I’d like to upgrade them to 10 day tickets. I was planning on doing that once we arrive, but I’m wondering if I should do it in advance so that I can make park reservations. Are there any other advantages/disadvantages to doing it in advance vs once we arrive? And how can I find out what the additional cost would be? I believed I purchased them in 2015 or 2016.