The StartShape property returns or specifies the starting shape for a blend effect.
Examples:
The following VBA example changes all blends to progress from yellow to green by changing the fills of the control shapes.
Sub Test()
Dim s As Shape
For Each s In ActivePage.Shapes
If s.Type = cdrBlendGroupShape Then
s.Effect.Blend.StartShape.Fill.UniformColor.RGBAssign 255, 255, 0
s.Effect.Blend.EndShape.Fill.UniformColor.RGBAssign 0, 128, 0
End If
Next s
End Sub