public void LoadToFile(string FileName, FileFormats FileFormat)
        {
            string format = GetFormat(FileFormat);
            string extension = GetExtension(FileFormat);
            using (ReportExecutionService rs = new ReportExecutionService())
            {
                
                
                ExecutionInfo execInfo = new ExecutionInfo();
                ExecutionHeader execHeader = new ExecutionHeader();
                rs.Credentials = new NetworkCredential(***, ***);

                byte[] result = null;
                string reportPath = string.Format(@"/{0}/{1}", reportFolder, reportName);

                rs.ExecutionHeaderValue = execHeader;
                execInfo = rs.LoadReport(reportPath, null);
                if (reportParameters != null)
                    rs.SetExecutionParameters(reportParameters, "en-us");

                string devInfo = null;
                string mimeType;
                string encoding;
                Warning[] warnings = null;
                string[] streamIDs = null;

                result = rs.Render(format, devInfo, out extension, out mimeType,
                    out encoding, out warnings, out streamIDs);
                execInfo = rs.GetExecutionInfo();
                using (FileStream stream = File.Create(string.Format("{0}.{1}", FileName, extension), result.Length))
                {
                    stream.Write(result, 0, result.Length);
                }
            }
        }

result = rs.Render(format, devInfo, out extension, out mimeType,
                    out encoding, out warnings, out streamIDs);