Cancel march invoice

In March,20 GSTR-1 we have filed One bills of outward in B2B table  and paid tax accordingly through March,20 GSTR3B  but  actual for Covid 19 purpose  there was no any movement of goods & Invoice and  party said cancel these invoice in MARCH,20 return BECAUSE  they already filled  Tax Audit return for the F.Y. 19-20

What is the way to rectify this error suggest us