This is probably a silly question - but can you upgrade a two day parkhopper ticket to an annual pass? I have enough money now to get the 2 day parkhoppers for the weekend we will be there. But in the meantime if I can manage to save up enough more I will want to pay the difference and upgrade our tickets to Annual Passes. Or do you have to buy an Annual Pass right off the bat if that is what you want to end up with? TIA!