Looking for assistance with this scenario and question. Requesting a thorough breakdown if possible to ensure I understand and I'm on the right track

The Situation: You are the project manager for a project that involves two departments in your company. The larger department is paying for 80% of your project. The smaller department is paying 20%. The department manager of the smaller department is requesting modifications nearly every week. Your stakeholder management plan was based on your company's standard template. You have been following the approved stakeholder management plan. You look at the issues log and see that there are four open issues. These open issues and possibly future requests for modifications could impact the completion date. The Assignment: Obviously something must be changed to better control this situation. What tools and technigues would you choose to control this stakeholder's engagement? What process outputs do yvou expect to create? What else, if anything, would you do? Prepare a response consisting of a minimum of 500 words. Include at least three credible references in addition to the PMBOKE Guide with at least one of these being a peer-reviewed journal article. Properly cite your response