عنوان مقاله [English]
نویسنده [English]چکیده [English]
Abstract. After contract is ratified, at the time of its execution, may be the contract commitments on the part of undertaker become so difficult or so expensive because of being put in emergency situation which itself may be due to the change of contract's conditions, or unexpected events. Although the principle of "strength of agreement" as a flawless principle‚ requires the necessity and execution contracts, law thinkers have tried to find a way to prevent the devastating effects of undertaking such commitments while considering the constancy of contracts. They have attempted to exempt the distressed from his commitment, or change the contents of the contract and match it to the new condition so as to be performable without much difficulty. In Iranian Law system, the possibility of contract revocation and adjustment has not been definitely accepted as a common rule in case of emergency situations; however, lawyers have tried to justify the possibility of revocation and adjustment of contract based on such principles and rules as" the rule of constraint" and denial of hardship and fault and also the theory of change of circumstances, and for affirming the aforementioned theory, they have referred to reasons such as implicit condition, created fraud, good faith principle and unfair possess.