In excel if you open a workbook and change anything then you are prompted with the save work when workbook ic closed. How can i reference whether a book has been ammended or updated so that i can diplay the saveAs dialog box instead in order to create audit trail.

What i really want is something along lines of

if workbook has changed/updated/ammended whatever then
application.dialogs.SAVEAS ETC

else
close
end if

This code will be activated from within a bigger piece of code that follows a number of criteria to decide whether to paste a new set of values in the worksheet