After a parliamentary enquiry into construction industry malpractice, changes occurred in collaborative practices between clients and contractors in megaprojects within the Dutch construction sector. The enquiry meant that both clients and contractors were forced to acknowledge illegal practices of collusion and fraud. For those engaged in public-private relationships, a process followed of attempting to change collaborative practices. Three interventions in collaborative practices are recounted: (1) organizing personal networks between clients and contractors; (2) a competitive dialogue procedure; and (3) the right of withdrawal. These three interventions helped to change first order practice, such as increasing mutual trust between client and contractor, supporting a mutual understanding of role positioning and dilemmas, and creating an understanding of the nature of the conflict but failed to change second order practices. Two contributions to the understanding of project management are provided. New empirical data are presented on the challenges that public and private partners face in their attempt to implement new collaborative practices. It is shown how power is entangled in the emerging of new collaborative practices. The findings are based on a longitudinal ethnographic study of public-private collaboration in the Dutch construction industry in the period 2006-11.