SQL Data Reader VS. ExecuteScalar

Currently my app checks to see if what a managers Email address is based on the department that an employee submitting a form is in.

It then sends an email to the manager notifying them that there is a pending requestl

This is shown in the following code:

string sEmail = null;
                            using (SqlCommand cmd = new SqlCommand(@"SELECT dm.ManagerEmployeeID
                                                                    FROM [PTO].[dbo].[Employees] e1
                                                                    INNER JOIN [PTO].[dbo].[DepartmentManagers] dm ON dm.DepartmentID = e1.DepartmentID
                                                                    WHERE e1.EmployeeID = @EmployeeID", conn))
                            {
                                cmd.Parameters.AddWithValue("@EmployeeID", sEmpId);

                                int nMgrEmpID = Convert.ToInt32(cmd.ExecuteScalar());

                                if (nMgrEmpID > 0)
                                {
                                    using (SqlConnection connCUDB = new SqlConnection(ConfigurationManager.ConnectionStrings["CentralUserDB"].ConnectionString))
                                    {
                                        connCUDB.Open();

                                        try
                                        {
                                            using (SqlCommand cmdCUDB = new SqlCommand(@"SELECT Email FROM Users WHERE AdjusterNumber = @PilotID", connCUDB))
                                            {
                                                cmdCUDB.Parameters.AddWithValue("@PilotID", nMgrEmpID);

                                                object o = cmdCUDB.ExecuteScalar();

                                                if (o != DBNull.Value)
                                                {
                                                    sEmail = Convert.ToString(o);
                                                }
                                            }
                                        }
                                        finally
                                        {
                                            connCUDB.Close();
                                        }
                                    }
                                }
                            }

                            if (!String.IsNullOrWhiteSpace(sEmail))
                            {
                                //email
                                MailMessage msg = new MailMessage();
                                //msg.To.Add("XXX@gmail.com");
                                msg.To.Add(sEmail);
                                msg.Subject = "PTO Request ";
                                //msg.From = new MailAddress("XXX@gmail.com");
                                msg.From = new MailAddress("jXXXr@pilotcat.com");
                                msg.Body = "A PTO Request has been submitted for your approval";
                                SmtpClient smtp = new SmtpClient();
                                smtp.Host = "smtp.gmail.com";
                                smtp.Port = 587;
                                smtp.EnableSsl = true;
                                smtp.UseDefaultCredentials = true;
                                smtp.Credentials = new System.Net.NetworkCredential("XXX7@gmail.com", "*");
                                smtp.Send(msg);
                            }
                        }

I was told that there would be certain situations that a department will have more than one manager.  So I need to somehow change the way I set them email value.

Someone mentioned that I could use a SQL Data Reader and put the info into an Array.

I'm just not sure how I would go about doing that. Can someone show me what I need to change in this code in order to accomplish this.

Thanks

JS