Yuck... sorry they threw a wrench in your plans.
My first reaction was that while it is always a pain to re-arrange days, that might be the easiest thing to do and just go to the party on Tuesday. But then I started thinking... that Tuesday would be the first Halloween party, right?
Since Labor Day is late this year I think the party is staring early, at least that's how it looks from the hours.
If that is so, then it would probably be pretty crowded (if not sold out). I'm always interested in some "extra" time at Disney. I'd say add the day and go on Friday.
I guess my thought process is you'll probably see equivalent crowds regardless which of the 2 parties you'd pick... but Friday just means an extra day there!
I would love the extra day, don't know if my boss would though
And as for the crowds, I went to
MVMCP this year on a night that was sold out. This was the third time I've done an MVMCP and the first one I've ever attended that was sold out. It was also the
least crowded MVMCP I've ever been to. I really think they're limiting how many tickets they sell for the parties now so that they are actually more worthwhile to attend.