The underlying data for the table is the manager ID.
You will need to create a query that will display the manager name and then import that information into Excel. In this way, the "underlying" data will be the manager's name.
SELECT *.Departments, ManagerName.Manager FROM Departments INNER JOIN Manager ON ManagerID.Departments = ManagerID.Manager
Obviously this SQL statement won't work because I don't know the table constructs but the concept contained with the statement is valid.