export as a pdf file using crystal report

I have code sample here, I can save as a PDF file directly but what I want to do is to show client first pdf file, and allow users to save it. How do I achieve this?

ReportDocument rpt = new ReportDocument(); rpt.Load(@"C:\CrystalReport2.rpt"); rpt.SetDataSource(datatablesource); ExportOptions rptExportOption; DiskFileDestinationOptions rptFileDestOption = new DiskFileDestinationOptions(); PdfRtfWordFormatOptions rptFormatOption = new PdfRtfWordFormatOptions(); string reportFileName = @"C:\SampleReport.pdf"; rptFileDestOption.DiskFileName = reportFileName; rptExportOption = rpt.ExportOptions; < rptExportOption.ExportDestinationType = ExportDestinationType.DiskFile; //if we want to generate the report as PDF, change the ExportFormatType as "ExportFormatType.PortableDocFormat" //if we want to generate the report as Excel, change the ExportFormatType as "ExportFormatType.Excel" rptExportOption.ExportFormatType = ExportFormatType.PortableDocFormat; rptExportOption.ExportDestinationOptions = rptFileDestOption; rptExportOption.ExportFormatOptions = rptFormatOption; >rpt.Export();