Party staff routinely see major turnover with a new boss and they had been alerted to expect such a move. However, the mass resignation letters will give Perez a chance to completely remake the DNC’s headquarters from scratch. Staffing had already reached unusual lows following a round of post-election layoffs in December.

Immediately after Perez’s selection as party chairman in late February, an adviser to outgoing DNC Interim Chair Donna Brazile, Leah Daughtry, asked every employee to submit a letter of resignation dated April 15, according to multiple sources familiar with the party’s internal working.

A committee advising Perez on his transition is now interviewing staff and others as part of a top-to-bottom review process to decide not only who will stay and who will go, but how the party should be structured in the future.