To edit an individual instance of a recurring event navigate to the single event view (the event details page) while looking at your calendar. Make sure that you are logged in and you have permissions to edit the event.
When clicking Edit this occurrence you will be directed to the backend event editing screen.
Once edited, click “Update” and these changes will then appear on the front end. This will also appear as a separate event in Dashboard >Events to make it easier for any further editing.