Every company is different, with different risks but here is the change management i have implemented successfully.
Minor, medium, major change category depending on potential impact with documented guidelines when each apply.
First release of a service always recommend to be major. (They are few vs daily changes and can be redtaped more to get many stakeholders requirements. Functional and non functional) Author of the change and his team decide the category.
- Minor need one more reviewer outside author. Team decide everything.
- Medium need min one more, and usually QA team or other affected team.
- Major change need CAB meeting with all major stakeholders to sign off.
CAB is responsible for the process and high level monitor the program, see if any cheating goes on, performance metrics such as number of changes per category etc. Help support people what could be considered minor vs major changes.
Overall rel flexible and balanced. Pushes people towards making smaller changes with less risk and at the same time increase velocity while still protect reasonable against bad actors, mistakes etc.
It is not perfect, medium changes tends to be more difficult to coordinate, some changes are missclassified etc but that is okey. It is not only about the process, communication matters and ci/cd have to be robust etc.
This balanced approach works for many.