If you are in an Approval Group, and a reservation is created that requires your approval, the notification bell by your name will light up with a yellow circle. Selecting that bell will take you to the Approvals page, where you can reject or approve pending rooms and resources.
Select Reject or Approve to apply to all requested rooms or resources in that event, or Selective to choose which rooms and resources to approve.
When the room or resource is approved or rejected, the event owner will receive an email letting them know.
If a room or resource has been approved but needed to be rejected, go to the event to remove the room or resource, add it back, and then reject it.