Hi NHNaz, yes you can change the addresses of the fixtures and all the scene and switches etc will update and follow. If you want, JUST to be safe, make a copy of your saved .shw file, or back it up somewhere. I always do this when I am implementing changes to my show. always have a back up.
It's very simple, click on the fixture page you want to change the addresses, then go to page tab, then settings, then patch, click on the small moving head icon and then drag around to your desired new address anywhere in the patch window and once your done hit OK.
Try it and let me know.