onComplete function call

Ola Senors e senoritas!

I’ve got this problem which has made me go all emo :sad:
If you create a class in as3, for instance:

I have a file called rootHandler.as with the following call
var myClass = new wootClass()

How do you get wootClass to call a function inside rootHandler.as once it’s completed, say loading some XML? Hence I want the class to revert back to rootHandler.as once it has completed some task by calling a specific function in that parent.

If anyone can help it will be the awesomeness. Thanks!