hint-request

hey there

i m quite new to procmail and its configuration

how do i get formail's output back into procmail to have it saved in the
specified location instead of in $DEFAULT ?, where it ends up now

        :0 fhw:
        * ^Subject:.*bla
        | formail -k -X Subject -X Date
        $DEFAULT/bla/

tks i.a., 
oswald