Welcome to the forum. There are two ways to change which model a drawing is referencing. I believe the simplest is using SW Explorer. You can probably find detailed instructions here with a search, but if not let me know and I or someone else will be glad to help.
One way here. Save what you have to make sure you have the current latest copy saved. Then save as the new number. Then close it. Then do a File/Open, select the new number file, and then hit the References button at the bottom. This will let you redirect the drawing to look at the new part. Then open and clean up.
Thanks for the extremely quick help everyone. I guess the main item I was missing was the added "open" options that you are presented with when you open a file within SolidWorks instead of just using windows explorer. Thanks again!