11 U.S.C. § 1101

In this chapter— (1) “debtor in possession” means debtor except when a person that has qualified under section 322 of this title is serving as trustee in the case; (2) “substantial consummation” means— (A) transfer of all or substantially all of the property proposed by the plan to be transferred; (B) assumption by the debtor or by the successor to the debtor under the plan of the business or of the management of all or substantially all of the property dealt with by the plan; and (C) commencement of distribution under the plan.