Question: I’m interested in “phased” retirement. How do I sign up?

Answer: You can’t, unless your agency agrees to offer it to you.

In phased retirement, employees eligible for retirement and with at least 20 years of service switch to half-time work for as long as a year. They receive a prorated salary plus half of the annuity they have accumulated to that point. When they later retire fully, they receive full annuities, including credit for the part-time work.

The idea is to benefit employees ready to cut back but not yet to retire fully, while agencies gain from having them pass along institutional knowledge — they are to spend a fifth of their working time mentoring others.

If you’re interested, try making a case for how the agency would benefit, versus losing you to immediate full retirement. But don’t get your hopes too high; because the authority is relatively new and the process is complex, agencies haven’t used it much.

Currently, there are only 276 phased retirees, about one in every 1,000 federal employees who are retirement-eligible, and just 21 agencies have any — NASA is the “heaviest” user with 43. Another 103 people have completed such periods.