No power conferred upon the district under the provisions of sections 46-301 to 46-315 shall be exercised if in express conflict with the original plan or project submitted to the vote of the electors of the district under the provisions of sections 46-302 to 46-305, unless and until approved by the affirmative vote of a majority of the qualified electors of the district at any general election or at a special election called for the purpose. At such election the notice of the election, conduct of the election and canvass of votes shall so far as practicable conform to the foregoing provisions for elections held for the purpose of the initial establishment or acquisition, by the district, of electric light and power plant, lines or systems.