For the booking organiser, you need to do the following;

1. Open Outlook.
2. Open your Personal Calendar.
3. Highlight the resource booking that you wish to cancel.
4. Right click on the selected resource booking.
5. Select Cancel Meeting.
6. This will remove the booking from your personal calendar and the resource calendar at the same time. If you try to delete the meeting directly from the resource's calendar itself, the booking will NOT delete.

NOTE: This could take up to 1 minute for the cancellation to update on the resource calendar.