The effect of the fundamental change of the situation on the contract in Iranian jurisprudence and law

The principle of the necessity of contracts as an inviolable principle and rule dictates the necessity and execution of contracts, but sometimes the execution of a contract based on this principle causes irreparable damages to the other party. Therefore, jurists have been looking for this discussion for a long time that, despite the principle of the necessity of contracts, in case of a fundamental change in the circumstances, which causes extraordinary burden and difficulty in the implementation of the contract and disturbs the contractual balance, can it be dissolved or adjusted? Or did he decide to amend the contract? The theory of the fundamental change of the situation that has been proposed in the western law tries to answer this question. This theory has been considered and accepted in the laws of different countries as well as in international legal documents including conventions. According to this theory, if circumstances arise, a contract can be terminated or modified. In this article, the theory of change of circumstances and its effects are examined from the point of view of Iranian jurisprudence and law. The purpose of the article is to find an answer to the question, can we find examples in Iran's jurisprudence and law that are consistent with the conditions and works of the mentioned theory? If the mentioned theory is acceptable in Iranian law and jurisprudence, what effects can it have on the contract?