Extra invoice in GSTR1

Client has erroneously included proforma invoice in GSTR1 and filed it. Is there a way to remove it from GSTR1?

Now for filing GSTR3B, he needs to pay amount for those proforma invoices as well, else the return will not proceed. What is the way-out here? Can he declare a lesser amount in GSTR3B (removing the amounts of proforma invoices) and later on in next month raise credit note for these invoices.