Как на VBA отменить выполнение действия в AutoCAD?

Sub Example_StartUndoMark()
    ' This example creates a series of lines, each with an undo marker
    ' defined for it. After lines are created, you can switch to AutoCAD and type
    ' the Undo command, and only one line at a time will be undone. If StartUndoMark
    ' call is not made, an undo in AutoCAD will undo all the lines at once.
    Dim line As AcadLine
    Dim stPnt(0 To 2) As Double
    Dim endPnt(0 To 2) As Double
    stPnt(0) = 1: stPnt(1) = 2: stPnt(2) = 0
    endPnt(0) = 2: stPnt(1) = 1: stPnt(2) = 0
    ' Create the lines
    Dim j As Integer
    For j = 0 To 3
        ThisDrawing.StartUndoMark
        Set line = ThisDrawing.ModelSpace.AddLine(stPnt, endPnt)
        stPnt(0) = stPnt(0) + 3
        endPnt(0) = endPnt(0) + 3
        ThisDrawing.EndUndoMark
    Next
    ZoomAll
End Sub

ThisDrawing.SendCommand "Undo 1"