How can I change events properties

[ghost]

Hi, I need to update one specific event color or date, but its properties can not be modified. I want this:

                var event = Event(Color.RED, dateClicked.time)

                if(filtradosEntradas?.size > 0 && filtradosSalidas?.size > 0){
                    event.color = Color.GREEN
                }
                else if(filtradosEntradas?.size > 0 || filtradosSalidas?.size > 0){
                    event.color = Color.BLUE
                }

But I get "Val cannot be reassigned" on "event.color = XXX" lines.