Log into booking engine.
Click Room Reservation Report.
Enter the Reservation Reference.
Click Search.
Click the [details] link to the right of the reservation.
Select the Room(s) you wish to cancel and click the cancel rooms for this booking link.
Enter any comments if you wish and choose whether to send the cancellation email to the guest or not then click cancel selected rooms.
The system will then tell you the reservation is canceled in the Process cancellations window.