find serial number in RMS database

I have a problem and i want someone help me. A saler who use the POS operator create a new serial number (bad serial number which is not in the availabled serial number list) to sell a particular item. I look for a good table in the database to change the bad serial number with the good one. I thing find it in the table named serial. The surprise i have, the view of the product inventory show me the good serial number as what solde (in the POS MAnager), but when i try to review the tiket i saw the bad serial number. i'm not still see where the report find out his serial number. I need for your help. please answer me