title: How do I submit another pull request once the first one was merged?
body: <p>I forked a public Github repository, cloned the fork to a local repo, made some changes, pushed them to the master branch of my fork. Then I opened a pull request and it was merged into the original repo.</p>
  
  <p>Now I want to make next changes. I do them locally, push to the master branch of my fork and try to open another pull request. Github shows both the new changes and the previously merged changes as belonging to this new pull request. Clearly I only want the new changes listed.</p>
  
  <p>What am I doing wrong and how do I do it right?</p>