$ git commit -m "Something terribly misguided"             # (1)
$ git reset HEAD~                                          # (2)
<< edit files as necessary >>                              # (3)
$ git add ...                                              # (4)
$ git commit -c ORIG_HEAD                                  # (5)
  1. Your last commit
  2. Sencond step above, illustrates how to move your git-head one commit back.
  3. Make changes - Remove changes which you didn’t want.
  4. Add your new changes.
  5. Commit those changes ✅👍 - You’re all set.