(APS logon code snipped and you need the SI_ID of the instance - left as a exercise for the reader ;-)
' Get the RPT file
Set ceInfoObjects = ceInfoStore.Query("Select SI_NAME, SI_UISTATUS, SI_FILES From CI_INFOOBJECTS Where SI_ID=" & Cstr(lInstanceID))
sFileSpec = "c:\temp\myReport.rpt"
ceInfoObjects.Item(1).Files.Item(1).CopyTo sFileSpec
' Export the RPT file to PDF
Set crApplication = CreateObject("CrystalRunTime.Application")
Set crReport = crApplication.OpenReport(sFileSpec)
crReport.DisplayProgressDialog = False
crReport.ExportOptions.DestinationType = 1 'Disk
crReport.ExportOptions.FormatType = 31 'PDF
crReport.ExportOptions.PDFExportAllPages = True
crReport.ExportOptions.DiskFileName = "c:\temp\myReport.pdf"
crReport.Export False 'Don't Prompt
' Free file handle and delete RPT file
Set crReport = Nothing
Set crApplication = Nothing
Set srFileSystem = WScript.CreateObject("Scripting.FileSystemObject")
srFileSystem.DeleteFile(sFileSpec)