You don't need 'formal training' for listening. Just listen. You can do this by finding things of interest in the person you are listening to. Even if you think this person is the most boring person in the world, you can remember that they are human and have some things that are valuable in their lives. And if you really think they don't, you can try to understand why not.
If you can learn to discover interesting things in anybody's life, then you will naturally be able to listen to anybody; and gain from the experience.