In this paper, we investigate a way to promote the reuse of legacy tools (or transformations) in specific contexts (defined by specific metamodels). More precisely we suggest a model transformation approach to achieve this purpose. We first introduce a language based on a metamodel called Modif in order to specify the differences between two se-mantically close metamodels. We can generate automati-cally data migration components from a Modif specification. They enable to put data complying with the specific context under the scope of the legacy tool. But more importantly in the case of a rewriting tool, they enable to put the tool’s outcome back into the original specific context. Then we propose a process and a set of helpers based on Modi...