If you need to amend or copy your event, locate it in your workspace calendar and click on it's title to load the event pop up panel.

If you click on the icon highlighted above a drop down menu will appear.

If you have invited attendees to your event and you change the time or date, a notification will be sent to them.

You also have the option to remove attendees from the event, again a notification will be sent to them.

Select 'Edit' from the drop down menu above.

Now click the 'Delete' button.