The DropShadow property returns EffectDropShadow for the drop-shadow effect.
Examples:
The following VBA example changes properties of the drop shadow applied to the active shape.
Sub Test()
Dim e As Effect
For Each e In ActiveShape.Effects
If e.Type = cdrDropShadow Then
e.DropShadow.Color.RGBAssign 255, 0, 0
e.DropShadow.Feather = 30
End If
Next e
End Sub