Hi Stefanie,
you cannot do an override for that as it's part of the controller functions of JEvents, so to change this behaviour bear in mind you need to modify core files and you will need to reapply your changes whenever you update JEvents.

A good starting point to this is taking a look at the method [i:3b5pye7e]editcopy()[/i:3b5pye7e] file: [i:3b5pye7e]/components/com_jevents/controllers/icalevent.php[/i:3b5pye7e] and checking the behaviour on each step.

Best!!