All existing ordinances and resolutions, administrative rules, regulations and practices, if not inconsistent or in conflict with this Charter, shall continue in full force and effect until repealed or modified by competent authority. All ordinances, resolutions, administrative rules, regulations and practices that are inconsistent or in conflict with this Charter shall, unless sooner repealed or modified, continue in full force and effect for a period of sixty days and at the end of that period shall, to the extent of such inconsistency or conflict, be of no further force or effect.