Sub x()
Dim oSld As Slide
Dim oShp As Shape
Dim rTxt As TextRange
Dim rFind As TextRange

For Each oSld In ActivePresentation.Slides
For Each oShp In oSld.Shapes
If oShp.HasTextFrame Then
Set rTxt = oShp.TextFrame.TextRange
Set rFind = rTxt.Find(FindWhat:="?")
Do While Not rFind Is Nothing
With rFind
.Font.Name = "Dotum"
Set rFind = rTxt.Find(FindWhat:="?", _
After:=.Start + .Length - 1)
End With
Loop
End If
Next
Next
End Sub