Do pensions impede phased retirement?

"Many workers reveal a preference for a gradual reduction in work hours as they approach retirement ("phased retirement"), rather than a sudden change from full-time work to full-time retirement. Pension regulations may impede phased retirement without a switch of employers by prohibiting access to pension assets. This study uses Health and Retirement Survey data to investigate the extent to which a gradual reduction in work hours is made difficult by pensions, particularly defined benefit plans. The study also explores other possible impediments to phased retirement"--Forschungsinstitut zur Zukunft der Arbeit web site.