What it covers. ITIL is a widely used body of guidance for IT service management, now published by PeopleCert. The current version, ITIL 4, describes a service value system and a set of management practices, including change enablement, incident management, problem management and service level management. It covers how normal, standard and emergency changes are assessed, authorised and recorded.
In practice. Organisations adapt ITIL practices to their own size and culture rather than adopting them wholesale. For change, that means a clear change model, defined authorities for each change type, a fast but controlled route for emergency changes and a record of what was changed, by whom and why. Auditors usually look for change records, post implementation reviews and links between incidents, problems and changes.
Common gaps. Emergency changes are often used to bypass control and are never reviewed afterwards. Processes can also become heavy paperwork that teams route around, so records stop reflecting reality.