Islamic jurisprudence, despite its steadfastness in principles, possesses the necessary flexibility to adapt to the changing conditions of time and place. One of the fundamental issues in this regard is the topic of changing legal rulings, which in contemporary times has been highlighted under terms such as "dynamic jurisprudence." However, precisely determining the rules and frameworks for changing legal rulings, in order to prevent misinterpretations and maintain the effectiveness of Islamic jurisprudence, is an unavoidable necessity. This study, with a descriptive-analytical approach and using reliable jurisprudential sources, examines and compares the criteria for changing legal rulings from the perspectives of both Shia and Sunni scholars. The findings of the research indicate that scholars from both sects believe in the possibility of changing legal rulings and consider factors such as changes in the opinions of jurists, social conditions, and transformations in the subject of the ruling as reasons for such changes. However, differences in the interpretation and application of these criteria are observed in some cases. Based on the results, it can be concluded that changing legal rulings is both possible and, in specific conditions, necessary. However, such changes must occur within a defined framework and in accordance with legal principles to prevent any form of extremism or excess.