To change the feedback mode during a session, simply press the F3 key to toggle through the available feedback modes. Text at the bottom of the screen will tell you what feedback mode you are in.
Pressing Shift+F3 will bring up a list of available basic feedback modes.
Pressing Shift+F3 a second time will bring up a list of available advanced feedback modes.
The feedback mode can also be changed when you are planning a session.