Cancel Command (Net Bios, 35h)

        This command is used to cancel a previous command. The address
        of the NCB for the previous command is passed in BUFADR. No-wait
        mode is not allowed for the cancel command. The following
        commands cannot be canceled: RESET, CANCEL, ADD NAME, ADD GROUP
        NAME, DELETE NAME, SESSION STATUS, SEND DATAGRAM and SEND
        BROADCAST. SEND and CHAIN SEND may be canceled, but the session
        will be terminated.