GSTR 1 return file

dear all,
we had sold material to an unregistered person for the month of July within the same state and also return file of July month,
for the month of aug ,the said customer the return apart of goods
now problem arises in gstr 1 ,when we filing gstr 1 for the month of aug ,such sales return to be shown in which column of gstr 1
hints sale value is 54000 and return is 20000