Upgrading tickets & question on Express

[MDer2FL]

DH, 3 kids and I will be staying onsite at Universal 6/29-7/2. Trying to decide on 2 or 3 day tickets. We haven't been there before, my two oldests are huge HP fans and that's probably where we'll concentrate our time. Since the crowds will be peak I figure we might need 2 days just for IoA, but would hate to buy 3 days if we find we can do both parks in 2 days after all. Can you upgrade a 2-day ticket to a 3-day pretty easily? Also, I plan on buying from UT. How does that work with the Express perk from the resort? Do they need to see your tickets or does everyone simply get an Express pass automatically, tickets or not?

 

[KorbensMomma]

Your express passes are based off of your room keys. You will take your room key over to a kiosk at the hotel, I think you swipe or scan the card and it will take your picture then print you a new plastic car with your picture on it.

I am unsure about the ticket upgrade question.

 

[damo]

You can upgrade if you like by just taking your ticket to guest services before the end of the second day. They will charge you the difference between what you paid and the price of the ticket you are upgrading to.

Your tickets are totally disconnected from your express passes.