You are able to edit a rooms record by going to the Room set up and clicking on Edit beside the one you want to change. This is highlighted in the image below.
Once you click on edit it brings up the screen below. It is within this section that you can change the description, location, colour and you can set the room to not be active anymore. You do this by un-ticking the Is Current checkbox.
Once you have made your changes click Update or Cancel to not save the changes.