All persons holding administrative office at the time the new form of government is adopted shall continue in office and in the performance of their duties until provision shall have been made in accordance therewith for the performance of such duties or the discontinuance of such office. The powers conferred and the duties imposed upon any office, department, board, or agency of the municipality by the laws of the state shall, if such office, department, board, or agency of the municipality by the laws of the state shall, if such office, department, board, or agency be abolished by this chapter, or under its authority, be thereafter exercised and discharged by the office, department, board, or agency designated by the council unless otherwise provided herein.