Can you upgrade a 1 day/1 park tkt?

[DISFANSHAN]

We have one day to spend at Universal Studios during our trip to Disney in August. It is difficult to determine if we will be able to fit both parks into one day. We will be traveling with DS12 and DS8. Our plan is to start at IOA. We will most likely hit the majority of the big rides there. IF there is time we would like to to US also.
My question is, if we buy a one day/one park ticket, use it at IOA, can we then upgrade that ticket to a one day/two park if we have time to hit US? Or would we be stuck buying another one day ticket?

 

[damo]

You can upgrade.

 

[macraven]

upgrade that ticket earlier in the day so you can hop to the other park anytime.

 

[DISFANSHAN]

Thanks for the replies!

 

[kris816]

We are buying 3 day one park tickets
If we use 2 days and just want to upgrade the third day to park to park

Can we?
How much per person would that cost?

 

[damo]

We are buying 3 day one park tickets
If we use 2 days and just want to upgrade the third day to park to park

Can we?
How much per person would that cost?

No. You would have to upgrade the entire ticket to a park to park.