How to call a function without the parenthesis?

programming flash
1 
// doc class
public function killschool():void {
   school = "dead";
}

//other class
private function whattodo(action:Function):void {
   var runfunc:Function = action;
   docclass.runfunc; // error, no property of runfunc found within the main doc class.
}
whattodo(killschool);

I know its possible, just not sure how.