Answer: Yes, it's possible. It's done by filing amended forms with the bankruptcy court. Depending on the particular schedule(s) that need to be amended, there may be additional court fees associated with the filing. If you're working with an attorney, this is not usually included in the attorney/client agreement, which means that your attorney may ask for more fees.
Generally, the failure to list a creditor can result in the denial of a discharge as to that particular debt. The reason for this rule is that it is unfair to creditors when a debtor's assets have been liquidated and the creditor is denied the chance to file a proof of claim and receive partial payment. However, some courts have adopted a "no harm, no foul" rule in "no asset" bankruptcy cases and debtors nonethless receive a discharge as to all debts.
About the Author: Carl H. Starrett II has been a licensed attorney since 1993 and is a member in good standing with the California State Bar and the San Diego County Bar Association. Mr. Starrett practices in the areas of bankruptcy, business litigation, construction, corporate planning and debt collection.