You can do that with a VBA recordset, or you can actually do it using a Delete Query.
If you create a new Field and set it's property to Indexed - No Duplicates.
Create an Update query that updates that field to Employee No & week ending date, i.e. Combine the 2 fields in to one, it will only update the first Instance of that combination.
That will leave the Duplicates with nothing in the new field, you can then run a Delete query that deletes records where the new field Is Null.