Although crises provide an opportunity for meaningful institutional change, the results often fall short of expectations because the reforms undertaken are informed by top-down, global-standard blueprints and fail to consider the informal, long-established, functionally credible institutions that exist at the local level. Seeking to explore how the interplay between formal and informal institutions can affect institutional change, the study focuses on Stagiates, a small community that has been struggling for more than 10 years against the uniform implementation of the 2010 administrative reform (prescribed in light of the Greek government-debt crisis), which threatens to dismantle their 350-year-old, functionally credible commons. To this end, the paper uses case study methodology, Historical-Institutional Analysis and Ostrom's Social-Ecological System framework. It concludes by emphasising the need for institutional analysis and policy to look more closely at the dynamic and complex dialectic between formal and informal institutions and the role that community needs, norms and values play in meaningful institutional change, paying due attention (as original institutionalism did) to the informality and the function-based social credibility of institutions.