Consistent stakeholder modifications of formal models via a natural language representation

While requirements described in Natural Language are inherently ambiguous and hard to check for consistency, they are intuitively understandable for domain experts. Using formal models, on the other hand, supports requirements engineers to specify requirements correct, consistent and complete. Transformations between these two different representations can become quite complex, since not everything that can be expressed with natural language can be captured in a restricted formal model. We describe a transformation approach that takes the formal modeling operations of story patterns and allows domain experts to transparently apply them on a natural language representation of these formal models. Also, a preliminary evaluation is presented.