Amendment in GSTR1 under B2B column

I have filed GSTR1  of august 2018 as nil return  but GSTR 3B has been filed with the values against the 2 invoices of the month of august 2018  because later it is found that there are 2 invoices(of B2B ) in that month which are not uploaded in GSTR1 .Now in the month of september 2019 can I upload those 2 bills in GSTR 1. As the party is asking to show that invoice in GSTR1 .Please suggest a solution as soon as possible.