The management of all changes to the components of a live infrastructure, from requests for change (RFC) through to implementation and review, to support the continued availability, effectiveness and safety of the infrastructure.
Change management within infrastructure is more Release & Deployment and the Change process and skills fit more into Business and Planning.
If we align though to ITIL V3 we would put Change management into Service transition.
If we align though to ITIL V3 we would put Change management into Service transition.