$ git rebase -i HEAD~n
This will prompt a vi console with options.
The n parameter indicates the commit quantity to edit in {creation time} ascending order.
Say you run $ git rebase -i HEAD~2; this will select the last two commits.
After this you will want to type i to enter insert mode in vi console and ESC to exit insert mode.
Find the commit to edit its message and replace pick for r (option description will be displayed in console).
Press : and write wq (write & quit) to save changes.
Edit your commit message, save changes and exit :wq.
Push changes $ git push -f.