There are a few reasons this could happen:
- You do not have write permissions to the resource calendar
- If you are the meeting requestor of an event and invited a resource, make changes within your own personal calendar (event) and send an update. If you need to cancel the meeting, do so within your calendar and an update will be sent to other recipients and the resource calendar.
- If there's an event you can't access that needs to be edited, contact the administrator of the resource for assistance.