Navigate to the Event you would like to cancel (see View an individual Event if you're unsure how to do this).
Click on the Cancel Event from the Toolbox area in the bottom left of the page.
A popup will ask you to confirm that you wish to cancel the Event and, by default, the Send event cancellation email box will be ticked. If you leave this ticked an automatic system generated email will be sent to notify the registered users that the Event has been cancelled.
If you would prefer to send a personalised email to the delegates using Email Reminders (prior to cancelling) or your own external email client, untick the box.
Click on OK to cancel the Event.