1、He was appointed as the plenipotentiary to negotiate the peace treaty.
他被任命为全权代表，负责谈判和平条约。

2、The ambassador acted as a plenipotentiary for the country, with the authority to make decisions on behalf of the government.
这位大使充当着该国的全权代表，拥有代表政府做出决策的权力。