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

    Deletes all logical names in the same or an outer (less
    privileged) access mode. If no logical name table is specified,
    the default is the process table, LNM$PROCESS. If you specify the
    /ALL qualifier, you cannot enter a logical-name parameter.