You can swap or switch rooms either from the booking itself or from calendar view
Swap from the "Calendar tab".Recommended as you get a better overview of how to stack or order bookings most effectevely.
1) Go to Calendar.
2) Click once one the booking you want to change and wait.
3) The booking will be animated, and all free units will be marked in green.
4) Grab the booking you want to move and drag it to the marked room you want to move it to.
5) Click ok.
Swap from the booking itself:
1) Open the booking.
2) Click on the "two arrows symbol"
3) Choose the room to pick.
(Observe if the hotel is full you need to create a swap room to move the bookings between the units. This will unfortunately affect the statistics. This will be updated in future versions of Sirvoy)