VMS Help CMS, REMOVE, GENERATION, Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The REMOVE GENERATION command removes an element generation from a
    class. The command does not delete the element generation from the
    library, but the element generation is no longer associated with
    the class.

    To remove one element generation from a class and replace it with
    another generation of the same element, use the INSERT GENERATION
    command with the /SUPERSEDE qualifier.