The scope verification process does not happen in the project planning process. It is included in the project plan, and it is scheduled in the project plan, but it doesn't happen during the planning phase.
Ideally, scope verification is done at the end of each milestone for the work done - however, most project managers prefer to execute this step when the project is done, as part of the project closure. The scope verification is often referred to as "acceptance" - and it is typically the client who performs the scope verification, by verifying that the features that should be in the project are there and are functioning as they should.
The scope verification process is needed to ensure that the client requirements are met in the project - and to protect the provider from any sudden changes that are not part of the scope.
The change process (or change request process) is a process by which the client asks for a new feature to be added to the project, or for a feature to be omitted or modified. The project will be re-baselined based on the duration and the cost of that change request.