to nullify /ˈnʌlɪfaɪ/ /ˈnʌlɪfaɪ/
to invalidate /ɪnˈvælɪdeɪt/ /ɪnˈvælɪdeɪt/
to annul /əˈnʌl/ /əˈnʌl/
to cancel /ˈkænsəl/ /ˈkænsl/
to repeal /rɪˈpiːl/ /rɪˈpiːl/
to void /vɔɪd/ /vɔɪd/
to render null and void