Script to change drawing substitutions

I was wondering if anyone has figured out a script to change drawing substitutions? How are they identified and what is the command to change them, or to connect changing them with a graphic control?

Hello,

Could you explain, maybe a little more what you want to do?
If you want an interface to change the drawings substitutions, all you have to so is to select your layer and then go to the Library window.

Let me know