FILA, the international wrestling federation, has confirmed that the date and site of the 2002 Women's World Wrestling Championships have been changed.    The 2002 Women's World Championships will be held in Halkida, Greece on November 2-3, 2002.    The best women wrestlers in the world will participate, competing in the seven new international weight classes for women's wrestling. This will be the first Women's World Championships held since the International Olympic Committee announced that women's wrestling had become an Olympic sport.    Previously, the event was scheduled for October 11-13 in Patras, Greece. Those making plans to participate in the Women's World Championships should note the change of date and site this year.