How to push a modified commit? If it is already in the repository.?

Question

git

git push
To github.com:
! [rejected] master -> master (non-fast-forward)
error: failed to push some refs to
hint: Updates were rejected because the tip of your current branch is behind
hint: its remote counterpart. Integrate the remote changes (eg
hint: 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

Answer 1

git push --force
Googling about possible problems yourself.

Answer 2

It also says in English in white what needs to be done.