In ergonomics, transforming work means understanding the actual activity to ensure that we distinguish between what is asked of man (prescribed task) and what is done to achieve the objective (actual task). It is an anchoring in the concrete that expresses itself beyond the material and organizational spheres alone.The ergonomic study was carried out in the ESAT (Établissement et Service d'Aide par le Travail) of an autonomous public medical-social institute with the aim of responding to a request for a project to fit out a new workspace that would accommodate the two poles of the establishment during the renovation work.The purpose of the approach was to support the project's stakeholders in making major organisational changes by questioning the existing situation. The aim was then to understand the future modalities of individual and collective work.The many issues highlighted led to the emergence of solutions adapted to the needs of the players in the activity and to the development of the institute's performance.