A Westchester school is imploring six high schools on Long Island to abandon their plans to skip a Model Congress event for students in New Rochelle out of fear stemming from a recent classroom stabbing. New Rochelle High School Principal Reginald Richardson said an official at George W. Hewlett High School told him his students won't participate in the March 23-24 event that culminates a year of debate at each of more than a dozen schools in the region.