Many long living distributed systems have to be extended dynamically. This implies that such modifications are not planned during the design time of the system. Thus it is necessary to implant a mechanism into such systems which allows to perform dynamic extensions. It is obvious, however, that such a mechanism needs to be based on semantic properties since otherwise non compliant extensions or modifications may lead to disastrous results. Such a mechanism is especially useful in an open setting e.g. CORBA offers, where the designer of a certain configuration of client and server objects cannot foresee when and how the configuration is extended. In this contribution we consider how such semantic properties can be expressed using graphs and how such graphs can be used with the help of graph rewriting techniques to express and handle various degrees of compliance between client and server object in a CORBA based distributed environment.