This paper analyses selected issues connected with exercise of the parties’ right to have their contract modified or terminated under Article 3571 of the Polish Civil Code. The paper aims at proposing a remedy to the practical consequences of the widespread interpretation which assumes that performance of the contract according to its terms as originally agreed by the parties makes it impossible to invoke Article 3571 in order to have the contract terminated or its terms modified by a court. As a result of the analysis undertaken in this paper, the relevant interim relief to secure the claim, as provided for in the Polish Code of Civil Procedure, is proposed as the above-mentioned remedy.