If you are no longer using a site or room you can delete this from your Arbor so it no longer appears to be booked.
To delete a site or room you'll need the School: General Admin: Administer permission. If you don't have this permission, ask your admin team to assign it to you.
Head to School > Timetable > Sites & Rooms > Sites (or Rooms).
Choose the site or room you want to delete and click on it.
On the next page, scroll to the bottom and click on the red Delete button. Finally, click on the red Delete button on the pop-up.