The publication of the European Agreement on Reforming Research Assessment (ARRA) in July 2022 is the latest, perhaps most high profile, attempt to date to steer research systems towards reform of how individuals, proposals and organizations are recognized and rewarded. While calls for reform are internationally-oriented in scope, not all countries, regions and organizations have moved with equal speed or enthusiasm to enact this agenda and there are uncertainties about what such change processes entail. This special session focuses on implementation of reforms within four ‘early adopter’ institutions from the Netherlands and Finland – where a national reform program exists – as well as Denmark and Italy. Speakers in the session have been involved in implementing reforms locally within their own research performing organizations (RPO). We will hear about the process they have gone through, opportunities and frictions they encountered and lessons learnt about resources and infrastructure needed to support such efforts. Being among the first movers in this space, their insights will provide valuable points for discussion, debate and learning for institutions and members of the STI community to engage with ARRA. The hybrid session was chaired by Janne Pölönen (Federation of Finnish Learned Societies) and Alex Rushforth (Leiden University), with a short introduction and Q&A discussion with the audience. Speakers included Sarah de Rijcke (Leiden University), Laura Niemi (University of Turku), Birger Larsen (University of Aalborg) and Francesca di Donato (National Research Council of Italy).