class ReportsModel
{
  public string CardNumber { get; set; }
  public string Item { get; set; }
  public string Units { get; set; }
  public string UnitsBonus { get; set; }
}

string connString = "Data Source=tcp:<nombredeServidor>.database.windows.net,1433;Initial Catalog=<nombreBasedeDatos>;Integrated Security=False;User ID=<usuario>@<nombredeServidor>;Password=<contraseña>;Connect Timeout=30";
SqlConnection conn = new SqlConnection(connString);
SqlCommand command = new SqlCommand("<Nombre de procedimiento almacenado>", conn);
command.CommandType = CommandType.StoredProcedure;
SqlDataReader reader;

List<ReportsModel> reports = new List<ReportsModel>();
try
{
  conn.Open();
  reader = command.ExecuteReader();
  while (reader.Read())
    {
    reports.Add(new ReportsModel
      {
        CardNumber = Convert.ToString(reader["CardNumber"]),
        Item = Convert.ToString(reader["Item"]),
        Units = Convert.ToString(reader["Units"]),
        UnitsBonus = Convert.ToString(reader["UnitsBonus"]),
      });
    }
}
catch (Exception ex)
{
  Console.WriteLine(ex.Message);
}
finally
{
  conn.Close();
}

List<string> file = new List<string>();
foreach (var item in reports)
{
  file.Add(item.CardNumber + "|"  + item.Item + "|" + item.Units + "|" + item.UnitsBonus);
}

createFile(file);

public static void createFile(List<string> file)
{
  string date = DateTime.Now.ToString("dd/MM/yyyy").Replace("/", "");
            
  string connftp = "<Direccion_de_servidor_ftp>" + date + ".txt";

  FtpWebRequest request = (FtpWebRequest)WebRequest.Create(connftp);
  request.Credentials = new NetworkCredential("<Usuario>", "<Contraseña>");
  request.Method = WebRequestMethods.Ftp.UploadFile;

  byte[] fileContent = file.SelectMany(s => Encoding.UTF8.GetBytes(s + Environment.NewLine)).ToArray();
  request.ContentLength = fileContent.Length;

  Stream requestStream = request.GetRequestStream();
  requestStream.Write(fileContent, 0, fileContent.Length);
  requestStream.Close();

  FtpWebResponse response = (FtpWebResponse)request.GetResponse();
  Console.WriteLine(response.StatusDescription);
  response.Close();
}