VMS Help SET, FILE, Qualifiers, /MODIFIED  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /MODIFIED

    Modifies the time value specified with the /BEFORE or the /SINCE
    qualifier. The /MODIFIED qualifier selects files according to
    the dates on which they were last modified. This qualifier is
    incompatible with the /CREATED qualifier, which also allows
    you to select files according to time attributes. If you do not
    specify the /MODIFIED qualifier, the default is the /CREATED
    qualifier.