How to interactively rebase-and-reword nth commit?

I think, one of the most frequent git features used is `rebase -i`. There's a common workflow I think everyone knows: you have commits 1, 2, 3, then you decide "Nah, 2nd commit needs a change", so you do `git rebase -i HEAD~2`, then in popped up editor you modify the `pick` on the first line to become `edit`, then you do the change, then `git rebase --continue`.

The boilerplate part here: even though you know that you want to edit HEAD~2, there is no way to tell git that right away. Every time you have to launch editor, edit the line manually, then save it, close it.

I have seen here some discussions about improving that, someone even posted patches, but I'm not aware if it went anywhere. So I created 2 years ago a shell wrapper `rebase-at`¹, which upon called as `rebase-at e HEAD~2`, does the thing described above automatically. Under the hood I simply substitute EDITOR with `sed` command that replaces `pick` on the first line (the HEAD~2 commit) with `e`. If used with shell autocompletion, it is now practically instantaneous.

I'm almost happy with `rebase-at`, except I don't know of any way to make it work with `reword` git action. You see, "rewording a commit" requires to run EDITOR twice: first to substitute `pick` with `reword`, and then to actually edit the commit message. But since EDITOR was substituted with sed, the 2nd run won't give you an actual editor to change the commit message.

Any ideas, how can I tell `git` that I want to "reword" nth commit right away? Sure, I am not the first one to stumble upon it, am I? Any ideas?

1: https://github.com/Hi-Angel/dotfiles/blob/0b9418224e4ce7c9783dbc2d9473fd1991b9b0b2/.zshrc#L148-L160