Sustainability is an ill-defined concept. Many actors make claims about what sustainability should be, and farmers react to such claims in different ways. How do change agents and their managers deal with this diversity of farmers’ attitudes towards change and towards the future of agriculture? How do they themselves cope with change and understand their role as change agents? We chose a comprehensive, action-training approach to answer such questions. This approach enabled the agents to acknowledge their historically-built professional models and to discuss some of the dimensions of their professional situations that needed to be grasped in order to develop new skills and adjust to new audiences, i.e.: the agent’s position among farmers and among the people acting to change farming practices at local level; the tension between on the one hand the agent’s engagement in promoting more environmentally-friendly practices or eco-systemic services and, on the other, the lack of support of his/her management or the farmers’ vision of the agent’s role; and the way of combining scientific and technical knowledge with farmers’ own knowledge, to enable the farmers to develop a new understanding of their unit of action (eco-agro-system versus agro-system) and, accordingly, new practices. It also highlighted the diversity of the agents’ points of view on change at farm level (discontinuity versus continuity) and the way to handle it: respectively by making the discontinuity visible and manageable at farm level, or by supporting a continuous change through step-by-step management of change at cropping-system level