The
process of
assigning a job or role to a person or thing.
Often prepended with "re-" to form retasking, which usually involves changing a person's job responsibilities to address new requirements.
For example:
When Sam arrived at the zoo, he was tasked as the Personnel Manager. Jenny decided to retask Sam from his eventual position as Vice President to Head Monkey Stroker after she found him gazing adoringly at the Chimpanzee House. It was to be her most egregious mistake, but the chimps never looked happier. Sam, too, incidentally.