Macro to change a Macro

I am currently working on a forecasting tool that has 100 workbooks around the world. The next level up consolidates these books right up to the top level. As i have so many sheets floating around i have created an admin tool that will auto-update these sheets. This works fine. I have now come to the point where one of these updates requires a change to the code in 'ThisWorkbook'. All the other updates are just macros stored in the admin book that run when required. Therefore i really need to change the code in one macro by use of another. Is this possible??? and if so how?? Thanks In Advance.....