Listening for an event in component

…inside your component definition:

created() {
  EventBus.$on('UserLoggedOut', payload => { ...do what your need - "this" is current component... 
  });
}

For example, I want to modify the prop: authInfo with the newely gotten payload

This is little bit tricky. Props are considered "input only" in Vue. Common pattern is "props down, events up" – meaning parent component owns the data (in its own data()), passes the data by props down to a child component and if the child component wants to change this data, it emits an event which parent listens to and in the handler change its internal data – new value will flow by reactivity and prop into the child.