I will try to describe as best as i can!

Starting in Column A9 downwards there will be a list of system names that
will updated by the user. From B9 downwards is the new password the user
enters. C9 downwards is the date the user changed the password, which again
is enetered by the user. Cell D9 will be locked, but is basically the formula
=C9+30, and will display the date the password will need changing. This date
is used by the macro to add the appoinment into outlook calendar. Cell E9 is
filled in automatically by my original macro which, once the appoinment has
been added, is filled in with 'Done'.

So when cell C9 date is changed, i want cell E9 to clear, so that when i run
the macro to add appoinments, which will be as a button, it will spot that a
cell in column E is empty and add that appointment