Problem when resetting JPanel and JFrame

I have the following java code:

miCalendarioGestor = new MiCalendarioGestor(profiles.obtainPerfil(comboBox.getSelectedItem().toString()));
            frame.getContentPane().add(miCalendarioGestor);
            frame.add(miCalendarioGestor);
            frame.repaint();

What I try is to reset my Calendar Manager to its initial moment, but this does not happen. Does anyone have any ideas? Thanks