Replace MC Instane names from variables AS2

Hi!
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 () {
clip1_mc.gotoAndPlay(“label1”);
};

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 () {
clipname.gotoAndPlay(“label1”);
};

Do you know the solution?
Thanks from Jotte