Changing GIT commit message from commit in history

$ git log
$ git rebase --interactive SHA_for_parent
Your editor will come up with several lines as seen in the image.
Change the word pick into reword in front of the commit you'd like to change.
A new file opens and you can edit the commit message.

$ git push --force
p.s.
to fix "Interactive rebase already started"

$ git rebase -i --abort