Good morning Ross,
from the Calendar or the Tableau, you can set up the Out Of Order on your rooms.
Double click on the PMS Room you would like to put out of order and click on Out Of Order
From here, you should select the dates and select Out Of Order.
You can also insert a note that will be shown on the Calendar.
As you can see, the option "Update Availaibility" is selected automatically.
This means, that the system will decrese the availaility by one unit on those dates and room.
On the calendar and tableau, you will see the Out Of Order in this way:
Talk to you soon!