Add Child and Remove Child on same button

Okay, so I have a movieclip on the stage(lets call that selection movieclip) that once a button is clicked is going to open another movieclip(call this slideshow) I am trying to remove the selection movieclip when you launch the slideshow movieclip.

citithmb_mc.addEventListener(MouseEvent.CLICK, clickHandler3);
function clickHandler3 (event:Event){
var workss_mc = new mc_workss();
var work_mc = new mc_work();