If i have a 3 day base ticket how much will it cost to add on to make it a 4 day ticket or 5 day ticket? Do i have to do this at the gate or can I do it at my hotel?
With the new "MyDisneyExperience" situation (where guests have a direct LINK between their specific tickets and themselves) it would appear that you could upgrade all the way until the end of the 14-day window from first use.
I know that is/was the case with tickets that were linked to guests via WDW resort packages. MDE accomplishes the same thing, even with non-package tickets.
Regardless, at the very LEAST, guests can upgrade as late as any time on the same day that the last ticket
asset was used.