Many UML CASE tools allow software engineers to draw diagrams and generate code skeletons from them. But often advanced users want to do more with their UML models, e.g., apply specific design patterns, generate code for embedded systems, simulate the functional and non-functional behavior of the system, run validation tools on the model, etc. which are very difficult to do with the scripting facilities offered in most UML case tools. In this paper, we describe UMLAUT, a freely available UML Transformatio- n Framework allowing complex manipulations to be applied to a UML model. These manipulations are expressed as algebraic compositions of reified elementary transformations. They are thus open to extensions through inheritan- ce and aggregation. To illustrate the interest of our approach, we show how the model of an UML distributed application can be automatically transform- ed into a labeled transition system validated using advanced protocol validation technology.