The situation is you have 2 managers managing 1 program with defined responsibilities which are distributed between these 2 resources. Now 1 of those resources is leaving for some period (6 month to 1 year) and you need to manage the takeover of the responsibilities.
change of the responsibilities, organization of the daily business, communication matrix etc.
1. Make sure the ToDo list is just up to your feasible workload and communicate what is above to manege before it will be signed off as you job. 2. Communicate before, during and after to all key stakeholders. 3. Have clear handover checklist and handover plan which will assure you will cover all topics. 4. At best collect all links, file locations etc and organize your work and supportive tools which will make your work approach much more efficient. There are many tools which can support it.