VMS Help MACRO, VAX MACRO Assembler, /UPDATE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /UPDATE[=(update-filespec[,...])]
       /NOUPDATE

    Positional qualifier. The /UPDATE qualifier cannot be used with
    the /LIBRARY qualifier.

    Updates the input file it qualifies by using the SUMSLP batch
    editor and the specified update file or files. By default, the
    assembler assumes that the update file has the same file name
    as the input source file and a file type of UPD. You cannot
    include a wildcard character in the file specifications. If it
    cannot find a specified update file, the assembler prints an
    informational message and continues the assembly.

    If you specify only one update file, you can omit the
    parentheses. If you specify more than one update file, the
    assembler merges the contents into a single list of updates
    before applying the updates to the source file.

    The /NOUPDATE qualifier has the same effect as not specifying the
    /UPDATE qualifier, or negates any /UPDATE qualifiers specified
    earlier in the command line. The input source file and update
    files are not changed by the update operation. The effects of the
    update appear in the compiled output. If you specify the /LIST
    qualifier with the /UPDATE qualifier, the assembler writes an
    audit trail of the changes to the listing file.