1. After invoicing, if a red invoice is required for sales return, the original invoice must be recovered and marked as "invalid" or valid vouchers of the other party must be obtained.

2. If an invoice needs to be reissued due to errors or incorrect filling, the original invoice can be reissued after the word "void" is marked. At the same time, if the special invoice is invalid after being issued because the buyer does not ask for it, it should also be treated as wrong filling.

3. In case of sales discount, a new sales invoice shall be issued after the original invoice is recovered and marked as "invalid"; It should be noted that if the special invoice is filled in incorrectly, it should be issued separately, and the words "incorrect filling is invalid" should be marked on the wrong special invoice.