The project manager should conduct a meeting with the project team to discuss and address the sources of disagreement, as this is a strategy for improving team morale and performance. According to the PMI website, one of the interpersonal and team skills that a project manager should have is conflict management. Conflict management is the process of resolving or reducing disagreements among project stakeholders, such as team members, sponsors, customers, or suppliers. Conflict can arise due to various factors, such as personality differences, communication barriers, resource constraints, or competing interests. If not managed properly, conflict can negatively affect the team morale, productivity, quality, and satisfaction. The project manager should use appropriate conflict resolution techniques, such as problem-solving, compromising, collaborating, smoothing, or forcing, depending on the situation and the desired outcome. The project manager should also facilitate open and constructive communication, encourage feedback and participation, and promote trust and respect among the team members1. By conducting a meeting with the project team, the project manager can identify the root causes and the impact of the disagreement, and work with the team to find a mutually acceptable solution. The project manager can also clarify the project objectives, scope, and requirements, and ensure that the team members understand their roles and responsibilities. By addressing the sources of disagreement, the project manager can improve the team morale and performance, and get the project back on track.
The other options, informing the stakeholders, crashing the project timeline, or issuing a change request, are not the best ways to deal with low team morale and disagreement. Informing the stakeholders may be a necessary communication activity, but it does not solve the problem or improve the situation. Crashing the project timeline may be a schedule compression technique, but it may not be feasible or effective, as it may increase costs, risks, or rework, and may also worsen the team morale and satisfaction. Issuing a change request may be a change management activity, but it may not be necessary or desirable, as it may imply that the project manager is unable to manage the project within the agreed baselines.
References: 2 Interpersonal and Team Skills - Project Management Institute 1 A Guide to the Project Management Body of Knowledge (PMBOKGuide) - Sixth Edition, Chapter 9.5