Three types of changes in the Operational Environment (Real changes, Events and day to day changes)

1. Real changes which require downtime or effects large portions of the production environment and need a communication process because they are planned need the change process the CAB - upgrade the app, new server, change IP etc
2. A failed device and its replacement is not a change it is an event, hard disk failure, reboot of a server because of a memory leak, use the change log to document, no CAB needed
3. Operational changes which require manual intervention should be documented in a change log so you know what has happened but these changes do not require a CAB, change to a system parameter, DNS name change, adding or removing a printer - This means the change can be reversed