The parties to a contract can agree to terminate the contractual relationship. The Agreement need not be express. It may be implied from what the parties have said or done. However the termination should not be readily implied. Only if that is clearly the intention of the parties should that result follow. When a contractual relationship is terminated by agreement the parties will normally regulate the effects of the termination. In the absence of that regulation, the effects are regulated by the rules to regulate those of a termination by notice with appropriate adaptations : Contractual relationship is retroactively terminated between the parties, but the termination is prospective in effect against the third parties. The termination by agreement does not affect liability for damages caused by past non-performance. A party who has received any benefit by the other s performance of obligation under the terminated contractual relationship is obliged to return it in accordance with § 548(Korean Civil Code). To the extent that the benefit is transferable it is returned by transferring it. However where the benefit is not transferable its value must be paid. The obligation to return a benefit extends to any natural or legal fruits received from the benefit.
Ⅰ. 대상판결(대법원 2005. 6. 9. 선고 2005다6341 판결)