"Due to unavoidable production delays, major elements of my tour stage design could not be available for me to rehearse on until this week,” said Katy Perry. “I’ll be spending the next few weeks taking the time to properly prepare the show to be an experience I am proud to share with you. I'm sorry for any inconvenience this causes, but hope everyone who sees the show will agree it was worth the wait. My first show on WITNESS: The Tour will be in Montreal on September 19, and all the rescheduled dates are listed on katyperry.com/tour. To my wonderful fans in Buffalo, I’m very sorry that we could not find a rescheduled date that worked. If possible, I would love to see you in Toronto."