This example changes all corner nodes to smooth nodes in shape three on myDocument
. Shape three must be a freeform drawing.
Set myDocument = ActivePresentation.Slides(1)
With myDocument.Shapes(3).Nodes
For n = 1 to .Count
If .Item(n).EditingType = msoEditingCorner Then
.SetEditingType n, msoEditingSmooth
End If
Next
End With