When you clone an event, a copy of the event is created. All attributes of the event are cloned except the attachment.
To clone an event from another calendar:
Select the event that you want to clone from any of the calendar views.
A balloon tool tip appears displaying the basic information about the event.
Click View Event Details link.
A new tab is created displaying all the attributes of the event in edit mode.
Click Clone Event.
A new tab is created and the cloned event in edit mode with the inherited attributes already available.
Edit the Event details to suite your requirements.
Click Save.