It is hereby intended by this act to reenact sections 17, 18, 19 and 20, as above amended, pursuant to the adoption of the amendment to section 21 of article 8 of the state constitution by vote of the electors on November fifth, 1912, so that villages under existing charters heretofore granted by the legislature shall have the same right and power to amend such charters as villages that have adopted complete charter revisions under the act hereby amended.