I wish to use a Data Validation drop down list to pick Employees from a
Named Range, but only those that do not have a leaving date within. My data
is dynamic. Say my employees are in Column S and Leaving date (blank if
still working) is in Column M.

I have it set up currently, but all my employees are listed, I only want
those that are still working to be listed. I guess its some some of filter
but not sure how its done

Thanks