If the result of the canvass shows a majority in favor of such change, then it shall become effectual on the date at which the next annual election of trustees would be held, and on such date the trustees shall surrender and turn over to the board or boards of supervisors the full and complete management and control of such district, together with all books, contracts, and other documents relating thereto.
Iowa Code § 468.535
89 Acts, ch 126, §2