try the added lines
'http://skp.mvps.org/ppt00025.htm#2
Sub pvtReplaceText(sOld As String, sNew As String, Optional bWholeWord As Boolean = False)
Dim oSlide As Slide
Dim oShape As Shape
Dim oText As TextRange
Dim oTemp As TextRange
For Each oSlide In ActivePresentation.Slides
For Each oShape In oSlide.Shapes
Call pvtReplaceText1(oShape, sOld, sNew, bWholeWord)
Next oShape
'added 6/17/2021
If oSlide.HasNotesPage Then
For Each oShape In oSlide.NotesPage.Shapes
Call pvtReplaceText1(oShape, sOld, sNew, bWholeWord)
Next oShape
End If
Next oSlide
End Sub