Dead Poodles is a famous rock band. The band's popularity is based almost solely on the vocals of the lead singer$,$ Rikki Leather. The band is engaged by Rock Promotions Inc to give a concert on Canada Day on Parliament Hill in Ottawa to an expected crowd of $100,000.$ The day before the concert, Rock Promotions receives a fax from Rikki stating that she will not be attending the concert because she is getting married that day. Rikki sends her sister, Candy Leather, to sing in her place. The concert is a big success. Even though the crowd is disappointed not to hear Rikki, they love Candy. Can Rock Promotions sue the Dead Poodles for breach of contract?