This article presents an analytical model to understand norm change through inter-subjective meaning-making. It applies this model to analyze how the United Nations and Syrian civil society actors defined the norm of civil society inclusion in the framework of the Syrian peace process. It shows that norm change happened through two interlinked dynamics: processes in which the actors built congruence between the inclusion norm and other salient norms in their normative environments and processes in which the actors inter-subjectively constructed the meaning of the inclusion norm. The article's contribution is twofold. First, it adds to the norms literature by presenting a multidirectional model of norm reformulation and providing fine-grained empirical data on it. Second, it contributes to the mediation literature by shedding light on the meaning of inclusion not just from an international perspective, but also from the viewpoint of domestic civil society actors.