Boomerang refers to an employee who quits to take another job and later returns to the company. 

职场“回头客”指的是辞职另谋职位后，又返回原公司工作的人。

Boomerang is an employee who is laid off and then rehired as a consultant or contract worker. 

职场“回头客”还可以指被解聘，之后又重新被雇佣为顾问或者合同工的人。

这种行为在英文中也称为Workplace U-turn。