linq to sql to convert a list into list of string

Question

i have a function in my wcf service like this:

public List<MyEmployee> FindEmployee(string uid)

        {

            DataClasses1DataContext context = new DataClasses1DataContext();

            var res = from r in context.MyEmployees where r.EmpID == uid select r;

            return res.ToList();

        }

i want to convert that list to alist of string and return it within this function,,how to do that?