When any vacancy occurs in the representation of the Commonwealth of Virginia in the House of Representatives, or when a representative-elect dies or resigns, the Governor shall issue a writ of election to fill the vacancy. Upon receipt of written notification by a representative or representative-elect of his resignation as of a stated date, the Governor may immediately issue a writ to call the election. The representative’s or representative-elect’s resignation shall not be revocable after the date stated by him for his resignation or after the forty-fifth day before the date set for the special election.