The Lighting Controller

I am deleting 2 dimmer packs, and added 8 LED DMX pars in place of them. I already have 12 LED pars programmed in steps 7 generator scenes. How can I add the 8 new pars without having to re-write entire scenes for my whole show? If you need more information, please be specific.

How can I add new fixtures to the scenes in my current show without re-programming the entire show?