1. Service faults which leads to change of service:
1. If the server violates the service order.
2. If the server doesnt execute the service properly.
3. If the ball touches a player of the serving team or fails to completely cross the vertical plane of the net through the crossing space.
2. Types of Delays:
1. Delaying a Substitution.
2. Repeating an improper requests.
3. Requesting an illegal substitution.
4. Prolonging other game interruptions, after having been instructed to resume the game.
3. Procedure of Substitution:
1. When a substitute enters the substitution zone, the second referee whistles and signals the request.
2. The first referee copies the substition signal, but does not whistle.
3. Second referee look at the players and sees the uniform number.
4. Then he authorizes the entry.
5. After the entry, second referee check with the scorekeeper.
6. Once the substitutions are recorded, second referee look for other requests and ensure the court is ready for play.
7. Put the wistle back in the mouth, move back in position, and give the ready signal back to the first referee.
