According to the PMBOKGuide, conflict resolution is an essential skill for project managers. The guide suggests that conflicts should be addressed early and in a private setting using an open and collaborative approach1. Direct communication with the functional manager to understand their perspective is aligned with these principles. It allows the project manager to identify the root cause of the conflict and work towards a resolution before escalating the issue or considering alternative options. References: PMBOKGuide - Conflict Resolution Strategies1; PMBOKGuide - Create a collaborative project team environment2.