“Delete event” removes the event from your account permanently with all its information including in the list of events on the calendar.
“Cancel event” disables access links. It does not remove the event from the list of events or the calendar. You can use “cancel” to maintain the list/calendar of your events in the past for archival purposes.
You may duplicate a canceled event by using “duplicate” icon in the “actions” column.
You can “uncancel” an event and use the same access links or regenerate new links in the “invite” screen.
To delete or cancel or uncancel an event find the event in the “events” list and choose the appropriate action in the “actions” menu on the right.