Acceptance or rejection of changes by supplier :
The amendments, modifications, or deletions made by recipient will be informed to supplier in form GSTR-1A. He can either accept or reject the details communicated to him on or before seventeenth day but not before fifteenth day of succeeding month. If he accepts the amendment, his return under section 37(1) of CGST Act [GSTR-1] shall stand amended accordingly – section 37(2) of CGST Act.
Thus, supplier has two days [16th and 17th of the month] to accept the changes made by supplier. Note that after tenth of a month, the supplier cannot add fresh invoice, credit note or debit note. He can only accept or reject.
If he accepts, it may result in short payment of tax. In that case, he is liable to pay tax with interest.