The implementation of Computer Based Systems (CBSs) is commonly guided by constraints imposed by the particular domain of the CBS. Domain-specific programming is a convenient way to provide a domain expert with a language that is customized to the particular constraints and assumptions of the domain. The careful thought and design that precede the development of any domain-specific visual language restrict the programmer from illegal formalisms, and allow for the rapid determination of the validity of the "program". Usually, the domain-specific visual language is designed and produced using a metamodel of some sort. Occasionally, similar domains can benefit from models created according to the ontology of this original metamodel, but usually some amount of model-transformation is required to give validity of the transformed models. This paper presents a visual language for transforming domain-models that can express the mapping between the meta-models of the "input" (i.e. the "old" domain) and the "output" (i.e. the "new" domain), and uses graph-rewriting techniques to transform the "old" domain-models into the appropriate "new" form..