Create a new branch for the current state, then move this branch back to the commit before the change, then apply all the changes of the commit you want to change (but not these updates) and re-commit. You will have to force-push, since the server-side branch will have different heritage; this is okay for now since no-one is using the branch anyway.

I think I could do all this for you but it would mean that you can't do any work on this branch until you get the updated version, and even then you might get some warnings / conflicts.

I'd say it's not worth the trouble, just make a new commit where you revert the change manually.