GitHub: Reopening a merged pull request

Question

The answer seems to be: You can't.

Once a pull request is merged and closed, it is locked forever and cannot be reopened. If your pull request is merged, closed, then your changes are pulled out (via force pushing backwards to before the merge), you will need to add commits to the branch and create a new pull request, copying all the details over and probably providing a link to the original pull request to manually save the history.

Might be a nice feature request for future GitHub.

I just successfully reopened a pull request by

1. Commenting on the pull request
2. Clicking the 'Submit and re-open' button which appeared on the comment form.

Just derive a new branch from the existing branch where you have done extra 1 commit. From there submit the pull request.

You can use the revert action:

It will create another pull request undoing all the changes did in the merged PR.