Advancement in demand side management strategies enables smart grid to cope with the increasing energy demand and provide economic benefit to all of its stakeholders. Moreover, emerging concept of smart pricing and advances in load control and communication generate new business opportunities as a third party entities between the electricity supply system and the consumers. In this research, a mathematical framework for the future third party energy service providers with an aim to benefit all the stake holders and also facilitate consumers to actively participate in Demand Side Management (DSM) by demand reduction bidding against power reduction with some constraints. This work also develops a novel scheduling algorithm with consumer retention for aggregated demand response in smart distribution network.