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

       /EXPIRATION=time (default)
       /NOEXPIRATION

    Specifies the expiration date and time of the account. The
    /NOEXPIRATION qualifier removes the expiration date on the
    account or resets the expiration time for expired accounts.
    The default expiration time period is 90 days for nonprivileged
    users.