Overwrite Sheet In Workbook With Sheet Of Same Name

I have created a workbook with several subsheets for different departments in my company to fill in there respective data that feeds a main sheet that colates all the info. I've designed a macro that basically breaks the department sheets into seperate workbooks so that i can send them to the different people to complete. When the files return, I could sit there pasting the data back into the main workbook but really I would rather have a macro that overwrites the sheet in the main work book with the completed sheet of the same name.

Maybe I havent done this correctly, but when i try to move the sheet from the department workbook back to the main workbook it just creates a (2) copy. I want it to replace the sheet rather than create a copy.