The Democratic National Committee asked for the resignation of all its staff members after former Labor Secretary Tom Perez was elected chairman of the party body at the end of February.

Leah Daughtry, a veteran DNC adviser and co-chair of Perez’s transition advisory committee, asked staff members to put forward resignation letters dated April 15, which NBC News first reported and The Huffington Post has confirmed.

The resignations are part of Perez’s effort to reform the DNC after a bruising election cycle in which the committee faced allegations of partiality toward candidate Hillary Clinton in the presidential primary race and in which Republican Donald Trump won the election.

Perez spokeswoman Xochitl Hinojosa said in a statement that the practice is routine following the election of a new chair.

“From the beginning, Tom has been adamant that we structure the DNC for future campaigns. Current and future DNC staff will be integral to that effort,” Hinojosa said.

“Over the last few months, the DNC staff has done incredible work under immense pressure to hold Trump accountable,” she added.

Sources within the DNC said that the resignations are part of an institution-wide evaluation and that they expect many current staff members to be kept on.

Will Hailer, who served as political director for Minnesota Rep. Keith Ellison’s bid to chair the DNC, is helping with the staff re-organization. Former South Carolina Democratic Party chair Jaime Harrison, who endorsed Perez after dropping out of the chairmanship race, is assisting in the transition as well.

Joshua Roberts / Reuters Tom Perez, the new chairman of the Democratic National Committee, has asked for resignation letters dated April 15.

The DNC already underwent a round of massive layoffs following the election in December.

Perez begins his term as DNC chair with a broad mandate to overhaul the party’s central-most body. Over the course of three months campaigning for the chairmanship in the hardest-fought contest in decades, Perez routinely promised to get “back to basics” by rebuilding the party at the state and local levels.

The perception of many grassroots progressives that the DNC favored Clinton over Sen. Bernie Sanders (I-Vt.) has by now been well-documented. Many establishment Democrats have even acknowledged the validity of their grievances. While campaigning for chair, Perez conceded that the process had been “rigged,” before walking back the comment.

But the DNC faces equal if not greater skepticism from state and local party officials who feel that the organization neglected them for the length of Barack Obama’s presidency. Critics of the DNC from diverse factions of the party lamented Obama’s establishment of Organizing for Action as a separate fundraising and organizing arm, arguing that it drained the party of much-needed energy and resources.

Perez now faces pressure to deliver on promises to make the DNC a less centralized organization, allocate more resources to state and local branches of the Democratic Party and create a more transparent system for awarding consulting contracts.

Since 2009, the Democratic Party has lost control of not only the White House and both chambers of Congress but nearly 1,000 state legislative seats as well.

Some of the DNC’s strongest progressive critics praised the decision to reassess the party’s staff structure.

“This is a good move,” said People for Bernie co-founder Winnie Wong. “It shows they are at least willing to take an inventory of the situation.”

Jane Kleeb, chair of the Nebraska Democratic Party, praised the move in the context of other steps Perez has taken to show his concern for the Democratic grassroots. Kleeb noted Perez’s support for elections in Nebraska and his show of solidarity with the children of Flint, Michigan, which he visited last week as a part of multi-state tour.

“I am pleased he is listening to everyone,” said Kleeb, who is also a board member for Our Revolution, the Sanders campaign successor organization. “And I’m really pleased that as Democrats we get to see Perez and Ellison standing together pushing back against Trump but also lifting up the issues that we care about.”

UPDATE: This story has been updated to include the names of people working on transition efforts and comments from progressive critics.