Two ways, if I understand
Option Explicit
Sub OnSlideShowPageChange()
Dim oPres As Presentation
Set oPres = ActivePresentation
With oPres.SlideShowSettings
.LoopUntilStopped = msoCTrue
.AdvanceMode = ppSlideShowUseSlideTimings
.ShowType = ppShowTypeWindow
.Run
End With
Select Case oPres.SlideShowWindow.View.CurrentShowPosition
'might be more flexible
Case 3, 5, 7, 9
With SlideShowWindows(1).View
.GotoSlide (.LastSlideViewed.SlideIndex), msoFalse
End With
Case Else
Exit Sub
End Select
End Sub
Sub OnSlideShowPageChange_1()
Dim oPres As Presentation
Set oPres = ActivePresentation
With oPres.SlideShowSettings
.LoopUntilStopped = msoCTrue
.AdvanceMode = ppSlideShowUseSlideTimings
.ShowType = ppShowTypeWindow
.Run
End With
'every odd numbered slide
If oPres.SlideShowWindow.View.CurrentShowPosition Mod 2 = 1 Then Exit Sub
With SlideShowWindows(1).View
.GotoSlide (.LastSlideViewed.SlideIndex), msoFalse
End With
End Sub