The Ecrins system is a tool for symbolic manipulation in process algebras. A process calculus is defined by the syntax and the conditional behaviour rules of its operators. From such a definition, the system builds an algorithm for evaluating the behaviours of the algebra terms. This computation is symbolic, and it can manage expressions with free process variables : the behaviours of such expressions are described by conditional operational rules. Another activity of Ecrins is the proof of equational laws w.r.t. strong bisimulation. Such proofs are used for proving correct intercalculi translations. We give the example of a translation from a subset of the Lotos language into the Meije-SCCS algebra, with some pieces of the validity proof.