According to the Project Management Body of Knowledge (PMBOK) guide, effective stakeholder engagement is crucial for the success of a project. The project manager should schedule regular meetings with the key stakeholder to provide updates and receive feedback. This will ensure that the stakeholder is kept informed about the progress of the project and can provide valuable input. Additionally, promoting an adaptive and transparent environment where the team can easily communicate with the stakeholders will help in building trust and improving the relationship with the stakeholder. References: PMBOK Guide, 6th Edition, Section 13: Stakeholder Management

Contingency control in the project and rebaseline is a process that involves adjusting the project baseline to account for the impact of unforeseen risks. This allows the project manager to update the project scope, schedule, and cost baselines to reflect the current situation and avoid further deviations. Integrated change control in the project is a process that ensures that any changes to the project are reviewed, approved, and communicated to all stakeholders. This helps the project manager to manage the expectations of the project sponsors, customers, and team members, and to maintain the alignment of the project objectives with the business needs. References: (Professional in Business Analysis Reference Materials source and documents)
* PMBOK Guide, Seventh Edition, Section 4.5.3, "Contingency Control"
* PMBOK Guide, Seventh Edition, Section 4.6.3, "Integrated Change Control"