[flash8]rollout old movieclip once new one is opened using buttons

ok I have buttons that open up movieclips…each one is on a different layer…now the problem is…i dont know how to make the old movieclip go away once the new button is clicked…what is the actionscript for this?

current code is…

[SIZE=1][COLOR=Blue]this.about_1.onRollOver = function() {
this.about_1.onRollOut = function() {
this.about_1.onRelease = function() {

[SIZE=2][COLOR=Black]“about_1” is the button “about_tb” is the movieclip its openeing

Now how do i make it so it will rollout the old movieclip to make way for the new one?[/COLOR][/SIZE]