TOPIC: Changing a management plan in a controlling process vs a planning process

The management plans (Cost, Schedule, Scope, etc etc) are created in a Planning process (for example Plan Cost Management creates the Cost Management Plan).
The PMBOK states that all (or almost all) of these Planning processes can occur several times to either create or update the plan. This is in line with the Progressive Elaboration concept, for example.

But many of the controlling processes have updates to these management plans as outputs. For example: I can update the Cost Management Plan in either the Plan Cost Management process or the Control Costs process.

How do I know when to use one process or the other when I need to change a management plan?
And when I need to implement an approved change request and update one of the management plans as a consequence of the change, what process should I use?

Updating a management plan and changing a plan may end up being two different things.
Your questions states 'change' a management plan, so you may want to use perform integrated change control process.
Your next question 'when' to implement...well that very well could be immediate depending on the approval.
The last part to 'update' a plan as a consequence; that also would be immediate.

Joao,

You are more likely to need to change your Project Management Plan or project baselines during a Control process than during the initial planning phase. If the exam forces you to choose between the two (which I consider unlikely), look at the situational context for reference, but likely the answer will be a Control process.

- Steven