23.1. When an election is declared void or the members of the winning formula turn out to be ineligible, the call for an extraordinary election should be issued within fortyf ve days following the end of the last stage of the electoral process.

23.2. In the case of vacancies of members of the Congress of the Union elected by the principle of plurality, the Chamber in question will call for extraordinary elections.

23.3. The vacancy of members of the House of Representatives elected by the principle of proportional representation should be f lled by the substitutes of the respective elected formula. If the vacancy is presented regarding the entire formula, it will be f lled by the formula of candidates of the same party that follows in the order of its respective regional list, after the corresponding representatives were assigned.

23.4. The vacancy of members of the Senate elected by the principle of proportional representation should be filled by the substitutes of the respective elected formula. If the vacancy is presented regarding the entire formula, it will be f lled by the formula of candidates of the same party that follows in the order of its respective regional list, after the corresponding senators were assigned.