APPENDIX K ITF RULES OF TENNIS During a tie-break game, players shall change ends after every six points. Additional approved alternative procedures can be found in Appendix V. case the players change ends at the end of the first game of the next set. Unless a fault or a let is called, the ball is in play from the moment the server  hits the ball, and remains in play until the point is decided. If a ball touches a line, it is regarded as touching the court bounded by that  line. 11. BALL IN PLAY 12. BALL TOUCHES A LINE 13. BALL TOUCHES A PERMANENT FIXTURE 14. ORDER OF SERVICE If the ball in play touches a permanent fixture after it has hit the correct  court, the player who hit the ball wins the point. If the ball in play touches a  permanent fixture before it hits the ground, the player who hit the ball loses  the point. At the end of each standard game, the receiver shall become the server and  the server shall become the receiver for the next game. In doubles, the team due to serve in the first game of each set shall decide  which player shall serve for that game. Similarly, before the second game  starts, their opponents shall decide which player shall serve for that game. The partner of the player who served in the first game shall serve in the third  game and the partner of the player who served in the second game shall serve  in the fourth game. This rotation shall continue until the end of the set. The team which is due to receive in the first game of a set shall decide which  player shall receive the first point in the game. Similarly, before the second  game starts, their opponents shall decide which player shall receive the  first point of that game. The player who was the receiver’s partner for the  first point of the game shall receive the second point and this rotation shall  continue until the end of the game and the set. 15. ORDER OF RECEIVING IN DOUBLES After the receiver has returned the ball, either player in a team can hit the ball. 451