how to focus on specific screen if there exists two same window application screen

I am testing Windows application, like Create New Member. After i input data in "New Member" screen and click on "Save" button, then click on "Add Dependent" button, it will open the "Add Dependent" screen and same as "New Member". Now it seems that TC always focus on "New Member" screen, so TC will failure when need to input data in "Add Dependent" screen. So how can i just focus on "Add Dependent" screen.