According to the BABOK® v3 Guide, the purpose of Plan Business Analysis Governance is as follows:

Planning what the processes are, who the decision-makers will be, and what information is required for effective decision-making around the requirement and design changes are very important in ensuring the governance business analysis activities run smoothly during the project.

Often in the real world, the planning of governance activities falls by the wayside and causes significant confusion and delay when it is time to approve requirements and designs. Change procedures are essential to facilitate the ever-changing nature of business needs, requirements, and ultimately, designs.

When planning the governance approach, the business analyst must give consideration of the following aspects and make sure to include them in their plans:

• What is the business analysis approach and how will work be prioritized?
• What is the change procedure? This entails consideration around who can ask for changes, who is involved in discussions and analysis of these changes, and ultimately, who is responsible for approving the changes?
• What type of documentation will be required for the changes?

So as you can see, most of the governance planning activities revolve around managing changes to business analysis information as it happens during the project.