Format options:

       /DESCENDANTS
       /NODESCENDANTS (default)

    Specifies whether CDO also purges children. When you specify
    the /DESCENDANTS qualifier, and your element is controlled, CDO
    deletes all children that are not also children of additional
    elements outside the area defined by your top collection. If the
    element is uncontrolled, CDO deletes all children that are not
    also children of any other elements.