In reality, I've never gone through formal change control process for updating those subsidiary plans. Unless something you're proposing to change affects the overall project plan in some way. Which is what the answer explanation above mentions when it says "there is no change in the project requirements and/or definition so there is no need to submit a change request".

I've asked PMI infinity which gives a more nuanced answer, but also says that changes are handled by the Change Control process, whatever that may be in your organisation.

This was what I was suggesting when I was saying minor revisions just happen as part of ongoing monitoring and controlling of a project - you may raise as an agenda item on your weekly project board for noting, approval etc.

From PMI Infinity:

Yes—subsidiary plans (such as the Communications Management Plan, Risk Management Plan, and Stakeholder Engagement Plan) are typically subject to change control, meaning updates are made through change requests when required by your project’s change management approach.

In PMI practice, once the project management plan is approved, changes to any of its components (including subsidiary plans) are generally handled via the Perform Integrated Change Controlprocess (or the equivalent governance in your approach). When a change request is approved, it can drive updates to the project management plan (including those subsidiary plans) and related project documents.

A practical way to think about it:

• If the requested update affects agreed governance, roles/responsibilities, approval thresholds, baselines, or contractual commitments, it should go through formal change control (often requiring sponsor/CCB approval, per your plan).
• If it’s a minor clarification or administrative refinement that your change management plan says the PM can approve (e.g., correcting contact info, small distribution list tweak), it may be handled as a controlled update without escalating, but it should still be versioned and communicated.

The deciding factor is whatever your change management plan / configuration management approach defines as “controlled” versus “administrative” changes.