From NAPUS:

Effective immediately, Postmasters in offices that are downgraded two or more grade levels as a result of Delivery Unit Optimization (DUO may voluntarily be placed non-competitively into other vacant positions…

This policy change is being implemented to allow Postmasters who have been reclassified to lower level Postmaster positions an opportunity for placement into other assignments that more closely approximate their skill set and former grade level without impacting salary. This policy change is temporary.

See complete letter from USPS Anthony Vegliante