🚀 go-pugleaf

I have a code in vdb  5.6
USE basename
SET FILTER TO
GO TOP
SCAN
 IF MYFIELD=SOMETHING
    DO SOMETHING (replace etc.)
 ENDIF
ENDSCAN


I'm trying to make something like this into vdb 7.1 but
I can't.

I tried
r=form.DATAMODREF1.ref.basename1.rowset
r.first()
DO WHILE NOT rowset.endOfSet()
   IF r.fields["MYFIELD"].value=something
      DO something  (r.fields["MYFIELD"].value=something etc)
   ENDIF
   r.next()
ENDDO

But I couldn't get the resoults that I expected. Can somebody please
tell me where
i'm making the mistakes?
Thank you.