If party forgot to file any invoice in b2b in gstr 1 of March can it be filed in April gstr 1 with March date

Reply- Yes, it can be filed in April return with March date.

As per proviso to section 37(3), no rectification of error or omission in respect of the details furnished under GSTR-1 shall be allowed after furnishing of the return under section 39 for the month of September following the end of the financial year to which such details pertain, or furnishing of the relevant annual return, whichever is earlier.