How to refresh/reload a page after using method from windows?

Question

I have a page that have a button to open a popup windows like this:

//in page.xaml.cs
   private void Add_Click(object sender, RoutedEventArgs e)
    {
        New_Window window = new New_Window ();
        window .Show();
    }

Then in a popup New_Window, i want to close the popup window and reload the previous page after a click method in a popup window. How do i do it ? thanks a lot.