9. Debit and credit note.—

Where a registered person has issued a tax invoice in respect of a supply made by him and as a result of cancellation of supply or return of goods or a change in the nature of supply or change in the value of the supply or some such event the amount shown in the tax invoice or the return needs to be modified, the registered person may, subject to such conditions and limitations as the Board may impose, issue a debit or credit note and make corresponding adjustment against output tax in the return.