Buses will run, school bells will ring, and the 2012-13 school year will officially get under way Thursday morning at 7:45 a.m.The new school year brings with it several changes including a new top official in Director of Schools Bobby Cox, a new school in Morrison, and a new principal at Centertown in Pam Cowan.Cox replaces former director Dr. Jerry Hale, who had served in that capacity since 2000.“We’ve done a lot of preparation this summer getting ready for the new year and it’s been pretty smooth to this point,” Cox said yesterday. “Hopefully that will continue Thursday when the kids go to school.”Grand opening ceremonies were held last Thursday for the new school in Morrison. It’s located on Five Mile Road away from the traditional Morrison downtown district.Cowan moves to the principal’s office at Centertown after 18 years in the classroom there.