Modifying a hotel reservation

We’ve decided to do a split stay for our trip this December. I need to modify our original ressie at Pop to be 2 nights shorter. When I try to do this online, it shows no room availability. Well obviously there is a room available because I have it booked!

If I call, will they be able to shave off those last 2 nights of my reservation? Also, will this jack up the room price to current rates instead of the lower rates from when I booked in April?

Call them… I was able to add a day to an existing reservation, when online showed no availability.