No convention shall hereafter be held for the purpose of altering or amending the Constitution of this state, unless after the legislature by a vote of a majority of all the members elected to each house has passed an act or resolution calling a convention for such purpose the question of convention or no convention shall be first submitted to a vote of all the qualified electors of the state, and approved by a majority of those voting at such election. No act or resolution of the legislature calling a convention for the purpose of altering or amending the Constitution of this state, shall be repealed except upon the vote of a majority of all the members elected to each house at the same session at which such act or resolution was passed; provided, nothing herein contained shall be construed as restricting the jurisdiction and power of the convention, when duly assembled in pursuance of this section, to establish such ordinances and to do and perform such things as to the convention may seem necessary or proper for the purpose of altering, revising, or amending the existing Constitution.