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

       /SCHEDULING_CLASS="class_name"
       /NOSCHEDULING_CLASS

    Adds a process to, or removes a process from, a scheduling class.
    This command does not modify the permanent class scheduling
    database file. Therefore, the effect of this command can be
    viewed as temporary placement into, or removal from, a scheduling
    class.