Code:
Sub CATMain()Dim oPartDocument As PartDocument
Dim oParameter as Parameter
Dim strFolderPath as String
Dim strPath as String
Set oPartDocument = Catia.ActiveDocument
Set oParmeter = oPartDocument.Part.Parameters.item("MyPartName")
strFolderPath = oPartDocument.Path
strPath = strFolderPath & Catia.FileSystem.FileSeparator & oParmeter.ValueAsString & ".CATPart"
oPartDocument.SaveAs strPath
End Sub