合同法合同的变更

HighTreesCasePromissoryEstoppelContractUnderSealAlsocalled“deed”FormalwrittencontractWithcorporateornotarystampInlaw,contractundersealisenforceableevenwithoutconsiderationParolEvidenceRuleAcontractundersealcannotbeamended/changed/variedbyoralagreementorwrittenagreementnotunderseal.Inotherwords,formalcontractcannotbechangedbylessformalagreement.Estoppel-definitionRestrain,prevent,stop,orbaraprincipleofcommonlawandofequitywhenaman,byhiswordsorconduct,hasledanothertobelieveinsomething,hewillnotbeallowedtodenyorchangeitwhenitwouldbeunjustorinequitabletheother.Isashieldnotasword.Estoppel:inprocedurelawEstoppelbydeed:cannotdenythetruthfulnessoffactsindeedruleofevidenceIssueEstoppel:ifcourthasdeterminedaissueinalegalaction,itcannotbearguedagaininanotheraction.CauseofActionEstoppel:AdisputecannotbetriedtwiceDoubleJeopardyReliance-BasedEstoppelEstoppelbyrepresentationoffactEquitableEstoppel:PromissoryEstoppel(hightreescase)Proprietaryestoppel(realestatecase)EstoppelbyrepresentationofFactAmakeafalserepresentationoffacttoB;AIntendedorknewBmayactuponit;Bactuallyacteduponininrelianceoftherep.InsubsequentlitigationbetweenAandB,Awasestoppedfromarguinghisrepresentationwaswrong,thereforevoid.UsedonlyasB’sdefenceEstoppelbyrepresentationofFactAvonCountyCouncilvHowlett(AvonCCcase)TeacherinjuredatworkReceivedsickpayforC.C.(theboss)paymenthigherthanthatprovidedincontractTeacherasked,C.C.said“nomistake”:afactC.C.foundmistake,overpaid1000poundTeacherhadspentthemoneySuedforunjustenrichmentEstoppelappliedPromissoryEstoppelAmadepromise(nostatementoffact)toB;Promisetoacceptalesspaymentofadebt;PromiseagiftPromiseacontractKnowingitwouldbeacteduponbyBBrelieduponthepromiseItisunconscionableforAtogobackonhispromiselater.PromissoryEstoppelAccordingtoLordDenningApromisew/oconsiderationislegallybinding:Promiseisintendedtobebinding,Intendedtobeactedon,IthasbeenactedonPromissoryEstoppelExceptiontotheconsiderationrule;Notacauseofactiononitsown,Bcansuebreachofcontract;Acannotarguedtherewasnotcontractb/ctherewasnoconsiderationMaterialFactsBycontractunderseal,plaintiffleasedbuildingtodefendantfor2500poundsperyearfor99yearsfrom1937Byaletter,in1940,becauseofwar,agreementmadetoreducerentto1250pounds.MaterialFacts-IIThereducedrate(1250peryear)hadbeenpaidfrom1941-19451945,receiverofPlaintiffaskedforfullrate(2500)tobepaid.Suedfor625poundsforSep.-Dec.1945PlaintiffArgued:The1940’slettercannotvarythelease:parolevidenceruleIfletterisanewagreement–voidb/cnoconsiderationgivenbydefendant.Reducedrenttemporaryendedin1945,notfor99yearsEstoppelonlyduringthewar.Defendantargued:Rentwasreducedto1250peryearfor99yearsbytheagreementin1940Noconsiderationvoidatcommonlawbutenforceableatequityifpartiesintendedtodoso.Parolevidencerule:equityallowDefendantargued:Equityallowsamendmentofdeedbyoralagreementtopreventpartyfromsuingunderthedeedifheagreetheamendmentearlier:BerryvBerryDefendantaguedEstoppel:plaintiffpromisedreducedrent,defendantreliedonthepromise,Pshallbeestoppedtodenythepromiselater.Defendantagued:Waiver:relinquishone’sright/privilegePlaintiffaccept1250poundsfrom1940-1945withoutprotestPwaivedtherighttoaskedforfullrentduringthisperiod.LordDenning:law1.Parolevidencerule:Incommonlaw,deedcannotbevariedbyoralagreementEquitycanonlyenforcetheamendmentifthereisconsiderationLordDenning:law2.Estoppel(oldlaw)OnlyapplytorepresentationoffactReductionofrentisnotafact,butapromiseEstoppeldoesn’tapplyLordDenning:Law3.Estoppel(newdevelopment)IfAmakeapromisetoBKnowingthatBwillrelyonthepromise,Bactuallyrelyonit;AwillbeestoppedfromdenythepromiseHence,Estoppelalsoapplytopromise.LordDenning:law4.Estoppel(newdevelopment)PromisorintendstobelegallyboundPromisorintendstobereliedonbypromiseePromiseeactuallyreliedonit.EquitywillnotallowpromisordenyitLordDenning5.Estoppel(newdevelopment)Thepromiseshallbeenforceableeventhoughthereisnoconsideration.InotherwordsAtcommonlaw,thereisnocontract,butatequity,thereisenforceablepromise.LordDenning:ApplicationPromiseofreducingrentisbindingbecause:PlaintiffintendtobelegallyboundKnewdefendantwillrelyuponDefendantactuallypaid1250LordDenning:ApplicationPromiseofreductionforhowlong?Reductiononlyapplytheperiodwhenthebuildingcouldnotfullyletb/cwar;Afterwar,fullyoccupied,promiseofreductionceasedtoapply.LordDenning:ApplicationPromiseofreductionforhowlong?Reductiononlyapplytheperiodwhenthebuildingcouldnotfullyletb/cwar;Afterwar,fullyoccupied,promiseofreductionceasedtoapply.Decision:FullrentshallbepaidfortheperiodfromSeptember–December1945HighTreesDoctrineObiterdictum:ifpromiseintendedtobebinding,intendedtobeactedonandinfactactedonitisbindingsofarasitstermsproperlyapply.PromissoryEstoppelItisanobiterWhyitisanobiter,notratio?合同法：合同的变更第77条当事人协商一致，可以变更合同。法律、行政法规规定变更合同应当办理批准、登记等手续的，依照其规定。第78条当事人对合同变更的内容约定不明确的，推定为未变更。合同法：合同的订立第10条当事人订立合同，有书面形式、口头形式和其他形式…法律规定或当事人约定采用书面形式的，应当采用书面形式。第11条书面形式是指合同书、信件和数据电文（包括电报、电传、传真、电子数据交换和电子邮件）等可以有形地表现所载内容的形式。第32条当事人采用合同书形式订立合同的，自双方当事人签字或者盖章时合