They would have to close the entire hotel and tear down the wings. Probably they could reopen the tower after the new shell and walls are done for the wings.
If you are familiar with the unique construction method used for the Contemporary, both tower and wings, you will understand why.
All the rooms were actually constructed at a location a few miles from the hotel using concrete and steel as individual components with the plumbing, wiring, fixtures and interior decor (other than moveable furniture) installed. The rooms were then hauled to the hotel site, and slid into the steel frames that had been built to accept the rooms.
The intent was to have "spare" rooms available so when they were to do a rehab, all they would have to do would be slide a room out and replace it.
However, they did not consider two items. One was that the concrete expanded more than anticipated due to the routine high humidity. The other is that they did not consider building settlement, which has an effect on twisiting the frame. Anyway, they found our that one everything was in place htey could not get the rooms out again.