Heiress and designer Nicky Hilton has canceled her show at Miami Fashion Week citing a "personal emergency." PageSix reports that the cancellation comes on the heels of a reported scuffle between Hilton and New York socialite Lydia Hearst at an Alvin Valley fashion show in LA earlier this week when Hearst was pulled from the front row of the audience to replace a model who had dropped out at the last minute. "When Lydia came out, everyone clapped but Nicky," said a witness. Hilton was "glaring at her from the front row." Hilton's rep denies any issues with Hearst and said, "The Miami cancellation was due to a scheduling conflict."source