The essence of this concept is the formation of a new contract, and this may occur in several ways. For instance, where both parties have obligations that remain unperformed, the contract may be discharged by mutual waiver. This is a new contract by which each party agrees to waive their rights under the old contract in consideration for being released from their obligations under the old contract: see Wilson (Paal) & Co A/S v Partenreederei Hannah Blumenthal, The Hannah Blumenthal [1983] 1 AC 854.