Replacing an object in an object oriented model in a computer system, by interrogating the model to retrieve information defining the relationships between the object to be replaced and other components of the model is described. These relationship definitions are then used to configure the replacement object within the model so as to assume corresponding relationships with the other components. There may be established as a part of the model functions to detect changes to the relationships between objects belonging to the model, and recording the changes in a registry. This registry is then interrogated to retrieve relationship definitions necessary to replace an object.