Replace MC Instane names from variables AS2

I am using AS 2.0 and Flash Player 9.
I want to change MC Instance names and target paths, by using variables.

As an example, this is the traditional working code.

enter_btn.onPress = function () {

I want to do someting like this.
This code does not work but it shows what I am trying to solve.

var clipname = “clip2_mc”;
enter_btn.onPress = function () {

Do you know the solution?
Thanks from Jotte