NFHS - A substitution request shall not be recognized if made by other than the head coach or a sub entering the sub zone.
Just double-checking my understanding: A request would not be recognized when....
- The player on the floor being subbed for calls/signals "sub" and/or comes to her side of the sideline above the attack line
- Team member on the bench calls/signals "sub" then stands and heads for the sub zone
- Team member calls/signals "sub" while on her way towards the sub zone, but several feet before entering it
- Assistant coach calls/signals "sub"