public void UpdateEmployee(string no, string firstName, string lastName, int index)
 {
     try
     {
         CronusReference.Employee emp = new CronusReference.Employee();
         emp.No        = no;
         emp.FirstName = firstName;
         emp.LastName  = lastName;
         index         = Employees.IndexOf(Employees.Where(e => e.No == no).FirstOrDefault());
         Employees.ElementAt(index).FirstName = emp.FirstName;
         Employees.ElementAt(index).LastName  = emp.LastName;
         cronusClient.UpdateEmployee(no, firstName, lastName);
     }
     catch (Exception ex)
     {
         Status = ExceptionHandler.GetErrorMessage(ex);
     }
 }