var ExampleBitmapData:BitmapData = ExampleBD();
var anotherBitmapData:BitmapData = anotherBD();
var bitmap_Holder:Bitmap;
bitmap_Holder.bitmapData = ExampleBD();
stage.addChild(bitmap_Holder);
stage.addEventListener(MouseEvent.MOUSE_CLICK, function(event:MouseEvent):void{
bitmap_Holder.bitmapData = anotherBD();
});
this can give you an idea i think.