the change management plan should be one of the first plans you developed in the project.
in the organization process assets you may find a template for this plan that you may tailor to match the project needs, and this template should include how organization identify, manage and control changes.
Moreover, it should include what kind of change control system, the organization used, and what procedures for approving and rejecting changes.
all this should be part of the PMIS as CCS is already a part of PMIS
we have to assume that a proper project management is already in place so the organization must have the above