Print-at-home tickets are your real tickets. If you want smaller tickets then order them as kiosk pick-up. Don't choose print-at-home if you have every intention of trading them in for other tickets. But the answer is yes, they can re-print them only at Guest Services and not at any of the ticket booths. They don't usually like to do this unless your print-at-home won't scan properly or they get wet or torn. They will do it as a courtesy but it causes some extra work when the Guest Service coordinator has to bank-out at the end of the night. So please, just choose kiosk if you want the smaller paper tickets. The larger tickets aren't a problem to carry because you can fold them up and put them in your lanyard. You only need them when you enter a park and not for anything else. Now if you have print-at-home express tickets, you will be using them for each ride so, in that case, I would choose kiosk pick-up. The print-at-home express are very difficult to reprint because often the online value is different than what is sold in the park that day and it can really mess up the transaction when they try to reprint those.
So, the answer is that all print-at-home can be reprinted no matter what the reason but please only ask for the reprint if your ticket is damaged. Otherwise, either live with your decision of choosing print-at-home or choose kiosk pick up and not print-at-home.
