On 28 August 2017,H .E Mr. Cheng Manith, Ambassador of the Kingdom of Cambodia to Lao PDR receive letter of H.E Mr. Thongloun Sisoulith, Prime Minister of Lao PDR addressed to Samdech Techo Hun Sen, Prime Minister of the Kingdom of Cambodia from H.E Mrs. Khamphao Ernthavanh, Deputy Minister of the Foreign Affairs of the Lao PDR at the Ministry of Foreign Affairs.