In the Flash authoring environment I can edit a library symbol and all on-stage instances based upon it reflect the changes. How can I do the same thing in ActionScript? There seems to be no way to address a library symbol.

For example:

Inside Flash CS3, I have created a Square.swf file that has 100 instances of the library symbol Square.

Now, Square.swf is loaded into another file BlueSquare.swf and I want to change the Square symbol into a blue square so that all instances of Square become blue.

How do I do this using Actionscript?

Thanks for the help.