New Zealand Professional Boxing Association president Lance Revill is prepared to strip Sonny Bill Williams of his New Zealand heavyweight title if he doesn't accept an invitation to fight the winner of Thursday's Joseph Parker v Afa Tatupu fight within six months but is prepared to enter into negotiations to delay the challenge. Promoter Dean Lonergan, of Duco Events, has challenged Williams' manager Khoder Nasser to accept a showdown between Parker or Tatupu, the current holder of the New Zealand National Boxing Federation title, with a $1.3 million winner-takes-all prize.