Substitutions
In lacrosse, substitution can occur in a variety of ways.
The primary method for substituting players is through the special substitution box, an area located between the two team benches that allows for on-the-fly substitutions. All on-the-fly substitutions must be through this "box."
Substitutions can also be made when the ball goes out on either sideline. In this case, if the coach desires to substitute players, he can ask for a horn to signify this "regular substitution". Play is delayed until the team(s) substituting have the players they want on the field. "Regular substitution" can also occur after goals are scored and penalties are reported to the scorer's table. These do not need a horn request.
Read more about this topic: Lacrosse Strategy