package for 2/add a day to one ticket

[StormyCA]

I know when you book a package, all the tickets must be for the same number of days.

I have a situation where I may be arriving early enough on our 'travel day' to make it worthwhile to add a day and go into the parks that day. My friend won't be arriving until evening and probably won't want to add for just a few hours (plus she'll probably be tired).

My question is; if I take only my ticket to the ticket booth will I be able to add a day or will they recognize it's part of a package and say both tickets must be upgraded?

Edit; package will be booked through WDTC direct or WDTC via Costco.