Top of the last inning and a pitching change is made by the home team, leading by 1 run. On his way back to the dugout, home coach reverses and heads back toward the field. He is just about to cross the first base line (for whatever reason, I don't know) and home plate says, coach, you can't go back out. Realizing that he would have to remove the pitcher he just put in the game, he nods and heads back to the dugout. Pitcher records the final out and the home team wins.
I'm very confused. What rules were being used?
In FED (HS rules), the coach can go out there, unless he has already used up all his conferences. In that case, the umpire is to refuse the conference.
IN OBR, the coach can go back out there, and it's the first visit to the new pitcher. No need to change.
If somehow the coach had already used his visit, and the pitcher hadn't completed facing a batter, then the umpire is to warn the coach. Even if the coach isn't warned (or ignores the warning), the requirement to face a batter supersedes this -- so the pitcher would have faced the last batter anyway.