I pulled off 3 nights one at a time on waitlist about 3 years ago. I had Sunday to Thursday booked at Paradise Pier. VGC was booked and I figured little chance. I planned to go to an airport hotel Friday night. About 2 months out, I noticed DCA was open late that Friday. So I decided to waitlist Friday in a studio. Came through in a couple weeks. Ok, so then I waitlisted Thursday, came through in a couple weeks. So then I did Wednesday, came through less than a month out. I then called Member Services and had them combined. That was it, I was out of points, I had another reservation I booked in the meantime.
The harder part was getting them to shorten the PP reservation. They would not do it because those dates were not currently available. They said ask at the front desk. I did and they reluctantly did it (room only).