经济合同法第6条规定:“经济合同依法成立,即具有法律约束力,当事人必须全面履行合同规定的义务,任何一方不得擅自变更或解除合同。”这是合同制度的一项基本原则,也是严肃合同纪律、保证当事人的合法权益和执行国家计划的必然要求,如果一方任意变更或解除,就是违反经济合同,要承担违约责任的法律后果。但是,当事人在履行合同过程中,由于情况的变化和各种主客观原因,有时会发生履行合同上的困难,需要变更 Article 6 of the Economic Contract Law stipulates: “Economic contracts are legally binding and the parties must fulfill their contractual obligations in full, and neither party may change or rescind the contract without authorization.” This is a basic principle of the contractual system . It is also a necessary contract for serious contract discipline and guaranteeing the parties’ legitimate rights and interests and implementing the state plan. Any change or dissolution by one party is the legal consequence of breaching an economic contract and assuming liability for breach of contract. However, due to the change of circumstances and various subjective and objective reasons, during the performance of the contract, the parties sometimes encounter difficulties in performance of the contract and need to change