Move branch pointer to different commit without checkout

git branch --force <branch-name> [<new-tip-commit>]

If new-tip-commit is omitted, it defaults to the current commit.

new-tip-commit can be a branch name (e.g., master, origin/master).

You can do it for arbitrary refs. This is how to move a branch pointer:

git update-ref -m "reset: Reset <branch> to <new commit>" refs/heads/<branch> <commit>

where -m adds a message to the reflog for the branch.

The general form is

git update-ref -m "reset: Reset <branch> to <new commit>" <ref> <commit>

You can pick nits about the reflog message if you like - I believe the branch -f one is different from the reset --hard one, and this isn't exactly either of them.