You can use Crystal Reports Export functions to save the report as PDF. Something like this:
report.ExportToHttpResponse(ExportFormatType.PortableDocFormat, Response, False, "YourReport")
or if you are using a Windows App
ReportDocument report = new ReportDocument( );
report.Load( reportURL );
report.ExportToDisk( ExportTypeFormat.PortableDocFormat , "yourFilePath" );
Hope this helps