As you move users from a pool, you can deactivate and remove the Front End Servers on the pool. After you have moved the last user from the pool, you can also remove the databases from the Back-End Database Server. As other server roles are removed from service, you can deactivate and remove the Office Communications Server 2007 software. For details, see in the Administering Office Communications Server 2007 R2 documentation.
For details on the user experience during this phase, see User Experience During Phase 11.