title: Is there anyway to change a mirrored (duplicate) repo back into a fork on github?
body: <p>I have my repo <code>private-repo.git</code> mirrored from <code>public-repo.git</code>. </p>
  
  <p>I would like to make <code>private-repo.git</code> public now and was wondering if I can rebase as a fork (as the only reason it was mirrored was to be able to have a private "fork").</p>
  
  <p>I have no intention of making a PR or merging changes. There are enough nontrivial differences from the source <code>public-repo.git</code> that <code>private-repo.git</code> has diverged into it's own project, but still has significant assets and source from <code>public-repo.git</code>. An analogy might be that <code>private-repo.git</code> is Waluigi, while the source repo <code>public-repo.git</code> is Luigi.</p>
  
  <p>I'd like to acknowledge the original project at any rate (beyond a mention and the stipulated license/copyright), and I believe the etiquette there is to fork <code>public-repo.git</code>.</p>
  
  <p>Unless I can preserve my full commit history and git log from <code>private-repo.git</code>, I would not want to fork <code>public-repo.git</code> and just do a massive add and commit.</p>
  
  <p>Any git wizards have ideas? Or is this just not possible?</p>