URGENT ! AS3 : Unloading a successfully loaded swf

1

Hi… i am currently workin on a flash website…
erm

the following works perfectly fine


 import flash.events.*;
    import flash.display.Loader;
    import flash.net.URLRequest;
    import flash.display.MovieClip;

        var req:URLRequest = new URLRequest( "main.swf" );
        var loader:Loader = new Loader();

            loader.contentLoaderInfo.addEventListener(ProgressEvent.PROGRESS, loadProgress);
            loader.contentLoaderInfo.addEventListener(Event.COMPLETE, loadComplete);
            loader.load(req);
			
			
			
       function loadProgress(event:ProgressEvent):void
        {
            var percent:Number = ( 100 / event.bytesTotal ) * event.bytesLoaded;
            
           trace( percent);
        }
 
         function loadComplete(event:Event):void
        {
            trace("Complete!");
           border_mc.addChild(loader);
		 
        }

how can i unload the current loaded swf when moving on to another frame?
kind regards
surf