Services provided by electronic means are becoming more and more popular. As a result, the significance of general terms and conditions (rules and regulations), which shape the content of the obligation relationship between the service provider and the customer, increases. This article describes the formal requirements that have to be met by a service provider in order to effectively amend the rules and regulations of services provided by electronic means. These requirements result primarily from Article 3841 of the Civil Code, although different views have formed in the doctrine and jurisprudence regarding the possibility of qualifying this provision as an independent, substantive basis for changing general terms and conditions. The authors consider whether it is necessary to include a modification clause in a template or contract in order to effectively introduce changes to the contractual relation of continuous nature. They also propose a model clause de lege lata based on the jurisprudence of the President of the Office of Competition and Consumer Protection, courts and statements presented in the doctrine.