novation　

novation　约务更替，债务更替文件　

Substitution of an original party to a contract with a new party，or substitution of an original contract with a new contract.Upon substitution，the obligations of the withdrawing-party are automatically discharged and no express-release is required.To be effective，however，the substitution must be agreed-to by all the original and new parties to the contract.Novation is never presumed；if the novation agreement is not in writing，it must be established from the acts and conduct of the parties.Novation is not the same as assignment of an agreement where no new agreement is needed and the rights and duties are transferred from the assignor to the assignee.