By default, a model-to-model transformation generates a model of a different level of abstraction, and a transformation user specifies a model file as the transformation target. As a transformation author, after you generate the source code for a model-to-model transformation, you can customize the code so that a transformation user can specify a Uniform Resource Identifier (URI), instead of a model file, as the transformation target. A transformation user can specify a new URI or the URI of an existing model.