git commit --amend -m "New commit message"
Then
git push --force
and you're done
$ git commit --amend -m "New and correct message"
git checkout branch_name
git commit --amend -m "Modified message"
# if previous commit is not pushed yet
git push
# or if previous comment was pushed in a previous commit:
git push --force-with-lease branch_name
git commit --amend
$ git push --force origin example-branch
git commit --amend -m "New commit message"
Then
git push --force
git push --force <repository> <branch>
git push --force-with-lease <repository> <branch>