The literature on collective action has poorly addressed processes of incremental institutional changes within organizations. This paper helps fill this gap by shedding light on how the community-based management of an organic label has changed following its formal recognition as a 'participatory guarantee system' (PGS). Ostrom and Basurto's (2011) analytical tool is useful to describe the changes in collective rules to address collective action problems that take place in standard-setting and labeling activities. Using original data collected from the Ecovida Agroecology Network – the oldest and largest PGS in Brazil –, we study the multi-scale changes in governance rules from the 1970s until today. We pay particular attention to the links between the institutional consolidation of PGS, its recognition by public authorities, and its adaptation to legal rules. We detail analytical operators indicating whether the introduction of the PGS rules at the national level was bottom-up or top-down. Our findings emphasize how local communities have been able to both adapt their governance system in response to the official arrangements concerning organic regulations, and influence national public arenas where these arrangements are defined. This form of co-management has been accompanied by a significant increase in the number of PGS-certified farmers.