Phased In or Out
Definition

Phasing In or Out refers to an arrangement in which employees who are joining or leaving an organisation move from a part-time position into a full-time position or vice versa. In some cases, employees are given the flexibility to determine how many hours and when they work to ease their transition into /out of a full-time position.

Phasing In would include new mothers returning to work on a part-time basis after maternity leave converting back to a full-time position. Phased Retirement is an example of Phasing Out.