What must occur if the same player number is listed more than once in the lineup?

When the same player number is listed more than once in the lineup, it is essential for the integrity of the game that every player has a unique number. This requirement helps officials and spectators identify players clearly, ensures accurate tracking of player substitutions, and maintains the overall organization of the match. To rectify the situation, the team must substitute players to ensure that all player numbers in the lineup are unique. This step is crucial to prevent confusion during the game and to uphold the rules of volleyball officiating.

The other options would not adhere to the regulations. Seeking approval from the referee or allowing players to continue playing with duplicate numbers does not resolve the issue of clarity in player identification. Similarly, taking no action would disregard the fundamental rule that mandates each player must have a distinct number. By substituting players and ensuring unique numbers, the team can comply with this rule and facilitate a smoother match experience for everyone involved.