Waltham - Mrs. Ursula K. (Regan) MacKenzie of Waltham died Wednesday, December 31, 2003 at Sunrise of Wayland. She was 76. Born in Waltham, a daughter of the late Thomas and Julia (Whalen) Regan, she was a lifelong resident of Waltham. A graduate of Saint Charles High School in Waltham, she had worked as an administrative assistant at Brandeis University in Waltham until her retirement. She was an active parishioner at Saint Charles Church and had been a member of the South Side Senior Citizens Club. The wife of the late Colin D. MacKenzie, she leaves her children, Colin D. MacKenzie, Jr. and his wife Carol of Plymouth, Kevin I. MacKenzie and his wife Patricia of Hampton, NH, Martin X. MacKenzie and his wife Jean, Ursula K. Weaver and her husband Jeffrey all of Waltham, Martha L. Calder and her husband William of Sudbury and Keith T. MacKenzie and his wife Katherine of Norwood; one sister, Julie Neal of Waltham; 10 grandchildren, 3 great-grandchildren and many nieces and nephews. Relatives and friends are invited to attend the Funeral at 10 a.m. Saturday from The Joyce Funeral Home, 245 Main Street (Rte. 20), Waltham followed by a Funeral Mass in Saint Charles Borromeo Church, 51 Hall Street, Waltham at 11 a.m. Burial will be in Mount Feake Cemetery, Waltham. Visiting hours are Friday 4-8 p.m. Memorial donations may be made to the Safe Return Program c/o Alzheimers Association, 36 Cameron Ave., Cambridge, MA 02140.