git checkout old_commit

<< - - - - changes in old commit - - - - >>

Retun to latest_branch and Discard the changes

git reset --hard

git checkout latest_branch

Retun to latest_branch and keep the changes

git add -u

git commit -m "changed in old commit"

git reset --hard

git checkout latest_branch

git reflog

git cherry-pick <old commit change hash>