If you've issued a B2C invoice with an Eway bill and need to change it to B2B after filing your GSTR 1, it is possible. You can alter the invoice and amend your GSTR 1 return in the current month's filing. This involves adding the GSTIN and reporting the changes, along with any additional tax liability in your GSTR 3B.
19 March 2021
Last February, i invoiced B2C bill to a party and take Eway bill on it. Later party asked me to change to B2B invoice. we already filed February GSTR 1 return too. Is it possible to alter the bill and any consequence if I alter the bill?