java – Change the value passed to void

In my main class, I create a Date variable that I want to modify later in another class. For that, when I create the new class, I call it like this:

calendar = new VCalendar (dateInput);

But in the VCalendar class:

public VCalendar (Date _date to return)
{
_date to return = new Date ();
}    

When I try to assign it a value in the following way, I can not and Eclipse tells me the following error:

The local _date variable to return defined in an enclosing scope must be final or effective

How can I change it?