I think about it this way. First someone or something (PM, Stakeholder, Risk Response, etc) requires a change. That is the first step.
Next, you, as the Project Manager, need to look at how this will impact the project. When you submit the Change Request, the CCB or other stakeholders are going to want to know the impact to the project.
After you know the impact, then it is ready to be submitted to the CCB. At the CCB, they are going to use your impact analysis to assist in making a decision.
Summary:
1. Change is identified
2. Impact Analysis or Assessment
3. Submit CR to CCB