Change Management describes the processes and practices needed to perform a change in a tech environment. These processes often include conditions and approvals needed, serving as checkpoints and tollgates.
The idea originates from ITIL, which for a long time was the favored way of practicing IT Operations.
Traditionally, organizations that do change management also implement change advisory boards (or CABs) as tollgates, where each change may get approval for execution in production. For a change to be considered by the board, one would first have to file a Change Requests.
In my experience, Change Advisory Boards are useless. It seems like the industry is catching on as well, given how stark the contrast is when practicing DevOps.