VMS Help DEASSIGN, Qualifiers, /EXECUTIVE_MODE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Requires SYSNAM (system logical name) privilege to deassign
    executive-mode logical names.

    Deletes only entries that were created in the specified mode
    or an outer (less privileged) mode. If you do not have SYSNAM
    privilege for executive mode, a supervisor-mode operation is
    assumed.