Changing y location on button press

1

I’m trying to get the y position of a movie clip to change upon a button press.

i thought, that by using the code below i could get it to move from y position 400 to y position 168.

Any ideas on where I went wrong?


changepos = function (display:String) {
	  movieclip._y = 400;
	  this[display]._y = 168;
}

button1.onRelease = function() {
	  changepos("movieclip");
}