Complex sentence: Once Vientiane released, Kou Voravong continued to fulfill his initial function of Governor of this province, then in 1947, became Governor of Khammouane Province (ຄຳມ່ວນ) whose capital is Thakhek (ທ່າແຂກ).
Split into simpler sentences: Once Vientiane released, Kou Voravong continued to fulfill his initial function of this province Governor. Then in 1947, he became Governor of Khammouane Province (ຄຳມ່ວນ) whose capital was Thakhek (ທ່າແຂກ).