In the scenario where a key stakeholder is not approving project deliverables, it is crucial for the project manager to directly engage with the stakeholder to comprehend the reasons behind the delays. This aligns with the PMI's guidance on stakeholder engagement, which suggests that understanding stakeholders' concerns and expectations is essential for project success1. By meeting with the stakeholder, the project manager can clarify any misunderstandings, align expectations, and work collaboratively to address any issues impacting the approval of deliverables. This proactive approach is recommended over merely documenting the issue or seeking influence from others without first attempting to resolve the matter directly with the stakeholder involved23.
References:
* PMI PMP: How to Handle a New Stakeholder's Complaint on Project Deliverables1.
* Planning effective stakeholder management strategies to do the same thing! | PMI2.
* Engaging Stakeholders for Project Success | PMI3.

The Project Management Professional (PMP) certification recognizes the ability of project managers to lead projects in any industry1. One of the key skills validated by the PMP certification is the ability to motivate people and teams through all phases of a successful project1. In the context of a self-organizing team, the role of the project manager as a servant leader is not to provide solutions, but to empower the team to solve problems independently. This approach fosters a sense of ownership, encourages learning, and promotes the development of problem-solving skills within the team. References: PMP Certification

According to the PMBOKGuide, integrated change control is the process of reviewing all change requests, approving changes, and managing changes to deliverables, organizational process assets, project documents, and the project management plan. It also involves communicating the decisions on the change requests to the relevant stakeholders. The project manager should evaluate the proposed change with integrated change control to determine its impact on the project objectives, scope, schedule, cost, quality, risk, and benefits. The project manager should also discuss the change with the project sponsor, who is the person or group that provides resources and support for the project and is accountable for enabling success. The project sponsor can help the project manager to obtain approval for the change, resolve conflicts, and align the change with the strategic objectives of the organization. References:
* PMBOKGuide, Seventh Edition, Section 8.2.2.1, "Integrated Change Control"
* PMBOKGuide, Seventh Edition, Section 4.4.3.2, "Project Sponsor"

The project manager should discuss the issue with the team members at fault and find out the root cause of why they did not fill out the status reports. The project manager should also remind them of the importance and urgency of the status reports for the project sponsor and the project success. The project manager should also work with the team members to establish a clear and consistent process for reporting the project status and ensure that they follow it. Reprimanding the team members, justifying their behavior, or quickly putting together a report are not effective ways to address the situation, as they may create resentment, mistrust, or inaccurate information. References:
* PMP Exam Content Outline, Domain II: Process, Task 4: Provide performance feedback and recognition to team members and other stakeholders.
* A Guide to the Project Management Body of Knowledge (PMBOK Guide), Seventh Edition, Chapter 3:
Project Performance Domain, Section 3.2: Team Performance, Page 77.
* Professional in Business Analysis (PBA) Certification Exam Outline, Domain IV: Evaluation, Task 4:
Communicate Solution Performance, Page 16.

According to the PMBOK Guide, the project manager should plan, manage, and monitor the communication activities throughout the project life cycle. The project manager should also consider the stakeholder needs, preferences, and expectations when choosing the communication methods, tools, and technologies. The project manager should also update the communications management plan as needed to reflect any changes in the communication requirements or approach. Therefore, the project manager should update the communications management plan based on the product owner's preferences and distribute it to the team.
This will ensure that the communication is effective, timely, and consistent among the project stakeholders. References: PMBOK Guide, 6th edition, pages 361-362, 368-369.