As a Program Manager; How to manage a delayed project from a PM from a different area/department

Colleagues,

I’ve just been assigned a new program, and one of the projects is currently in the implementation phase and significantly delayed. To make it more challenging, the Project Manager (PM) comes from a different area/department than mine, so we are not part of the same immediate team.

As you can imagine, the PM is fully focused on 'firefighting' to recover the schedule, making it very difficult to get their time for a proper onboarding or knowledge transfer. I want to start adding value quickly without becoming an additional burden for them.

What strategies do you use when taking over or overseeing a project in this state? How do you build rapport and gather critical information when the other PM is overwhelmed and from a different area/department? I’m looking for ways to be a partner in the recovery rather than just another person asking for reports.

Looking forward to your insights! Francisco