Canceling or Deleting Events
Only an event's organizer can cancel or delete an event.
When canceling an event, you can use the event record to alert attendees and to update the event's status. If your event is recurring, you can choose to cancel one instance or cancel the entire series of events.
Canceled and deleted events are removed from the calendar unless you enable the Show Canceled Events option in your portlet setup. For more information, see Calendar Portlets.
To edit events from the calendar, make sure you've checked the Edit Activities from Calendar box on the Activities subtab at Home > Set Preferences.
For more information, see the following:
Administrators can delete events in bulk for employees who are no longer with your company. See Mass Deleting an Employee's Events