If we told you then there's a chance that more people (including you) might do it which is the opposite of what igp wants because it is not an intended feature but more a glitch or bug.
Tbf if you look carefully and think you'd be able to figure out how it's done anyway.
We don't want it as it's not fair, it's also upset some of the guys that got relegated. That's why I'm asking as the person who has managed to get in shouldn't be allowed to stay in my opinion..
As the host of the league, you're well within your powers to remove him, however, I recommend letting the manager who joined in know why they were booted.