What is Change Control?

Legal Definition
Change control within quality management systems (QMS) and information technology (IT) systems is a formal process used to ensure that changes to a product or system are introduced in a controlled and coordinated manner. It reduces the possibility that unnecessary changes will be introduced to a system without forethought, introducing faults into the system or undoing changes made by other users of software. The goals of a change control procedure usually include minimal disruption to services, reduction in back-out activities, and cost-effective utilization of resources involved in implementing change.

Change control is currently used in various products and systems. For IT systems it is a major aspect of the broader discipline of change management. Typical examples from the computer and network environments are patches to software products, installation of new operating systems, upgrades to network routing tables, or changes to the electrical power systems supporting such infrastructure.

Certain portions of the Information Technology Infrastructure Library cover change control.
-- Wikipedia
Legal Definition
A documented, methodical process of documenting changes in activities, policies, procedures, requirements, by keeping up-to-date records available for all concerned personnel.