VMS Help CMS, REPLACE, Qualifiers, /VARIANT=variant-name  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Controls whether a variant generation is created. If you specify
    the /VARIANT=variant-name qualifier, the number of the created
    generation is the predecessor's number, followed by the variant
    name, followed by the number 1.

    The Variant Generation Names are limited to
    alphabetic characters (A through Z) and underscore
    characters with a maximum length of 255 characters.

    If two or more users have concurrently reserved the same element
    generation, the replaced generations cannot be on the same line of
    descent. Thus, one can be replaced as a main line generation and
    the rest must be replaced as variants.