受委派的英文：
on assignment

An ambassador is appointed to look after diplomatic business.
大使受委派办理外交事务。

assignable adj.
可分配的；可直定的；可归属的

give an assignment to (a person) to a post, or assign a task to (a person).
派某人到某个职位或分派任务给某人。

make the assignment for the next day
布置第二天的作业

fall to somebody by assignment or lot.
通过分配或者划分使某人垮台。

They tapped her for a reportorial assignment.
他们指定她去完成一次报道任务。