Library /sys$common/syshlp/uafhelp.hlb MODIFY, Qualifiers, /PRIMEDAYS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /PRIMEDAYS=([NO]day[,...])

    Defines the primary and secondary days of the week for logging
    in. Specify the days as a list separated by commas, and enclose
    the list in parentheses. To specify a secondary day, prefix the
    day with NO (for example, NOFRIDAY). To specify a primary day,
    omit the NO prefix.

    By default, primary days are Monday through Friday and secondary
    days are Saturday and Sunday. If you omit a day from the list,
    AUTHORIZE uses the default value. (For example, if you omit
    Monday from the list, AUTHORIZE defines Monday as a primary day.)

    Use the primary and secondary day definitions in conjunction with
    such qualifiers as /ACCESS, /INTERACTIVE, and /BATCH.