appoint sb to sth跟 appoint sb sth有什么区别

appoint sb to sth跟 appoint sb sth有什么区别
任命某人某个职位 不是appoint sb
为什么又来了一个appoint sb to sth 有什么区别?
appoint sb sth 应该是appoint sb to be sth的省略吧
就等于appoint sb as sth
可以appoint sb to do sth任命某人去做某事
那appoint sb to sth是什么东西？