To respond to one of my posts, create a post on your own website and make sure that it includes the permalink URL of the post on my site that you are responding to. Your post will then appear as a response on my post. This is called a webmention and they are a really cool way to allow websites to communicate with one another.
If you want to update or remove your response, then change or delete your post and re-enter your post's URL again. That's all there is to it!