When a project manager is informed during the planning phase that a certain activity cannot commence until another department has implemented the required IT system, the appropriate action is to include this dependency in the project schedule. This ensures that the project timeline reflects all known dependencies and constraints, allowing for accurate planning and resource allocation. Including the dependency in the schedule allows for transparency and sets realistic expectations for project stakeholders. It also facilitates better risk management as it highlights potential delays early in the process, enabling the project team to plan for contingencies.
References:
* The PMBOKGuide - Sixth Edition, which outlines the importance of identifying and documenting dependencies in the project schedule as part of the Develop Schedule process1.
* Best practices in project management that emphasize the need to account for all dependencies in the project planning phase to ensure a comprehensive and realistic project schedule2.

When a software development provider reports an issue that is blocking the other remaining deliverables, the project manager should schedule a meeting with the provider to collaborate on the options12. This approach allows the project manager and the provider to work together to identify potential solutions and decide on the best course of action2. It also ensures that the provider is involved in the problem-solving process, which can lead to more effective and efficient solutions12. Furthermore, this collaborative approach can help to maintain good relationships with the provider, which is crucial for the successful completion of the project12. References: ProjectManager, Unosquare