Modify method in Ember Component

In the Discourse I want to modify method _dock. The modifying code will be placed in plugin.

Here's short snippet from that file:

export default Ember.Component.extend({
  elementId: 'topic-progress-wrapper',
  classNameBindings: ['docked', 'hidden'],

  ...
  _dock() {
    ...
  },

});

How to modify this method? Should I reopen this component and what is a syntax for that?