' PathName of current model document
Dim sModelFullPath As String
sModelFullPath = swModel.GetPathName

' get path name without filename
Dim sFilePath As String
sFilePath = Left(sModelFullPath, InStrRev(sModelFullPath, "\"))

' get filename and extension
Dim sFileName As String
sFileName = Right(sModelFullPath, Len(sModelFullPath) - InStrRev(sModelFullPath, "\"))

' get filename without extension
Dim sFileNameWithoutExtension As String
sFileNameWithoutExtension = Left(sFileName, InStrRev(sFileName, ".") - 1)

' combine everything to new path name
Dim sNewFullPath As String
sNewFullPath = prefix & sFileNameWithoutExtension & "REV" & CurrRev & ".pdf"

' SaveAs with new full path
Set swExportPDFData = swApp.GetExportFileData(1)
swModel.Extension.SaveAs sNewFullPath, 0, 0, swExportPDFData, 0, 0