Katy Perry changes tour dates due to 'production delays'

Katy Perry says she's pushing back the start of her new tour because of "unavoidable production delays."The pop star's "Witness: The Tour" will now begin Sept. 19 in Montreal. Perry said in a statement Thursday that "major elements of my tour stage design could not be available for me to rehearse on until this week."The tour was originally planned to kick off Sept. 7 in Columbus, Ohio. Tickets purchased for the original concert dates will be honored at its new date. Refunds are also available at