Rewrite this sentence in a simpler manner: In 7 April 2016 he wasn't able to maintain his post in the party and stepped down from his position as Prime Minister.
Following the 12th National Congress of the Communist Party of Vietnam, Nguye ̂ ̃ n Ta ̂ ́ n Du ̃ ng wasn't able to maintain his post in the party and stepped down from his position as Prime Minister on 7 April 2016.