We propose a technique for combining devices to create a more flexible context-aware service system. This system integrates devices that are embedded or distributed in the user's environment and are networked with each other. The system for providing context-aware services locates and selects devices appropriate to the user's context. When the context changes while the service is being provided, devices for that service can be partially reconfigured without resetting all the parameters. We have verified the effectiveness of our technique in a prototype implementation.