The chaotic nature of economical, technological and social environment leads the need of operational approaches and tools helping managers to detect, to evaluate and to plan what are the required changes for their enterprises. This paper presents a software environment permitting to construct and to evaluate enterprise change trajectories allowing enterprise to go from its current state to a target state thanks to strategic objectives i.e. required performance. The first part details the main industrial and scientific issues of the work. The second part presents the generic approach which is adopted. This approach is decomposed into six steps detailed and illustrated. Before concluding, the third part describes the corresponding developed open tools implementing this approach and some results examples.