If a B2C party bill was mistakenly added to your B2B transactions, you cannot directly revise your GSTR-1. Instead, you need to issue a credit note for the incorrect invoice in the following month's GSTR-1 to nullify the transaction. You should then ensure the B2C transaction is correctly reported in subsequent months.
26 May 2020
Hello Querist , You need to issue credit note for that invoice in your next month GSTR 1 to nullify the transaction and report B2C which missed to be reported .