We present a study of a first step in a large-scale intervention designed to shift lab instruction away from tightly prescribed lab norms. The intervention was implemented in a national network of Professional Learning Communities of high school physics teachers (N=250) operating in a high-stakes exam setting with limited resources, and catering to diverse groups of students. A pre-intervention survey examined learning goals that the teachers value as well as practices taking place in their lab lessons. The findings revealed a gap between the importance that teachers attributed to scientific practices such as experimental design and the manifestation of these goals in the national lab exam. In addition, the survey revealed disparities between the scientific practices that teachers believe that their students engage in during the instructional lab and the practices they identify in physicists' work in research labs. The intervention consisted of a series of Restricted Inquiry Labs (RILs) designed to address the teachers' interest in change as well as the constraints imposed by the setting in which they work by modest restructuring of traditional labs such as encouraging students to reflect on the considerations underlying the experimental design. The intervention proved successful in that half of the teachers reported that they introduced the RILs. They described students' engagement when granted more autonomy in designing an experiment, as well as students' difficulties in coping with a more open-ended task. Implementation of the RILs also created challenges in class management. Despite these challenges, most teachers reported that they intended to keep using RILs. Teachers asked to re-design assessment policies to emphasize scientific inquiry. The RILs proved to be a feasible way to introduce change towards inquiry-oriented labs via professional development programs, while pointing out aspects that need to be addressed to respond to teachers' concerns.