In the last years there has been a high production of groupware systems. However, most of these systems have been based on the desktop metaphor. We propose a translation process based on the use of the conceptual model (or, particularly, on the task model and the data model) of the original application. From this model and by means of a pattern-based reengineering process, we obtain mobile versions of the original systems. In this paper the user interface reengineering process is described and an example of the application of patterns for the evolution of a specific system, Domosim-TPC, is shown.