In the Program model, the Program is the all-encompassing container. When a program is created, it just assumes the duration from the beginning to the end of the current year. But, as you add projects within, its duration changes to accommodate the duration of the projects. The program duration always spans its projects. It takes the earliest start date and the farthest end date from among all of the project dates. If a project duration extends or retracts, Amplify will automatically update the program duration to accommodate that. 

The same is true for projects. It is the duration of the project items that dictate its timeline.  The project duration will span its impact, cost, and schedule data. Even though you can set the project start and end date when you create it, with every update of impact, cost or schedule duration outside of the project's existing period, that date gets automatically adjusted.

So, you want to be careful while revising the dates of these objects. Fortunately, the Gantt chart can help you manage this effortlessly.   If all applicable features are enabled, Gantt can show bars for all projects, impacts, costs, risk review dates, resource capacity, demand, goals, tasks and milestones. 

You can click and drag any bar to change its duration. This way, you can view and assess the impact on the other items in the project while altering the dates on a particular item. If the dates of any of the items are set outside of the current duration, then the dates of parent items change to accommodate that. And when the overall schedule duration changes, the project duration gets updated.  

The Properties tab for projects and programs automatically switches to the date of their schedule.

If an archived or restored item has dates that affect the overall schedule duration, the project and program dates adjust accordingly.