Amount difference in Eway Bill and actual invoice amount

I issued a debit note to supplier of Rs.80,000(inc. tax) the same value mentioned in EWB and same uploaded and filed in GSTR1 .

but now after delivery of goods back to the supplier,supplier is refunding only 50% value of the debit note that is 40,000 (inc. reduced tax amount ) .

Can I amend debit note in GSTR1 by reducing amount and tax value which will be different and less from the amount I mentioned in EWB .