Nearly 20 years of initiatives to join up health and social care...have not led to system-wide integrated services”(Glasby, 2017). Whilst the national and local governments are investing funds and promoting policies for encouraging health and social care integration(HSI), there is a paucity of experience that put this integration into practice. Having a supporting policy that facilitates HSI is not enough for implementing that change. The challenges of integration can also arise from internal factors(e.g. communication, power, learning) and increase when dealing with actors outside the healthcare system with different financial incentives, working culture, legal requirements and tools for information sharing. 
 To overcome these challenges, this research investigates how practitioners and policy makers can foster HSI at meso level in the presence of a supporting policy. This paper supports healthcare practitioners in designing new effective strategies for HSI and advances the academic literature by investigating the internal and external drivers of HSI in the presence of a supporting policy. 
 This paper adopts a single exploratory case study methodology and studies the change management strategy that the Local Health Authority(LHA) of Milan implemented for promoting HSI in the eight healthcare organizations(HOs) of its area. This case was considered suitable because the Italian Government recently passed a policy on the HSI that has forced the integration at meso level between HOs and social organizations(such as municipalities and cooperatives). The data collection process followed sequential steps, whose aims were:
 •Studying the as-is level of HSI in each HO through an ad-hoc datasheet that was sent to the Health and Social Care Directors(HSCDs) of the eight HOs. This step helped the HOs to rethink their data using an unusual scheme and to raise awareness of their internal practices and resources;
 •Investigating the willing level of HSI(to-be) in each HO with eight in-depth interviews with the eight HSCDs and at least one member of their staff. Each interview was held by researchers and one representative of the LHA;
 •Informing HSCDs on the as-is and to-be HSI practices and encouraging the discussion about to-be scenarios through two informative and participative workshops, whose participants were the eight HSCDs and the eight members of their staff.
 Results revealed at least three interesting enablers of HSI. 
 First, the adoption of a participatory approach facilitated the exchange and comparison between HOs. During the debate, the HSCDs with low levels of HSI pinpointed their willingness to increase the level of HSI. Thus, this approach created a positive sense of competitiveness between HSCDs, generating bottom-up changes.
 Second, giving HSCDs the possibility to share and discuss the possible options of integration, which take into account the potential constraints of HOs(e.g. limited space or staff available), with each other guided them in choosing the most suitable changing strategy. 
 Third, giving HSCDs the possibility to adopt flexible piloting HSI solutions allowed them to adapt the process of change management according to the specific context: one HO that has to collaborate with many Municipalities and one Municipality that has to collaborate with many HOs.