To cancel an event session and delegates enrolments, you will need access to the Management Console and access to the Events Management.
To search for an event, go to Management Console and select Event Management. Select Search courses and events and use the search filters like Domain and Keywords to find the event and click Search. Once you have identified the relevant event, click Edit on the right hand side and the details of the event and sessions will open.
Each upcoming session are listed toward the bottom of the page, to manage the users who are enrolled or enrol users manually click Manage delegates.
Click Cancel session to cancel a specific event session for all users current enrolled. You can then enter in a specific message that will be included in the cancellation email and a reason for cancellation.