Former vice president Joe Biden has named Jen O’Malley Dillon as his new campaign manager, a major shake-up that comes as the party’s leading candidate plans an organizational expansion to prepare for the general election, according to a person familiar with the decision.

The move is intended to quell concerns raised in recent weeks by senior Democratic strategists about the leadership structure of the Biden campaign, which has been beset by underwhelming fundraising, scant staffing resources and organizational miscues during the early nominating contests.

The campaign shuffle is an acknowledgment that while Biden has had a remarkable recent run of victories – at least 15 of the past 21 contests – his operation would not be up to the challenge posed by President Donald Trump if Biden were to win the nomination.

After Biden performed below expectations in the Iowa caucuses, Anita Dunn, a senior adviser who previously worked for President Barack Obama, took operational control of the campaign, sharing responsibilities with Biden’s original campaign manager, Greg Schultz.

Schultz, who built the Biden campaign and oversaw initial hiring and delegate strategy, is expected to stay on in a new role that will involve organizational planning and continued outreach to donors and other stakeholders for the general election, the person familiar with the plans said. The person spoke on the condition of anonymity to discuss internal campaign strategies.

Dunn, who also helped Biden prepare for a possible 2016 run for president before he decided not to run, will also continue with the campaign, returning to her role as a senior adviser to Biden.

An operative with deep ties across the party, O’Malley Dillon, 43, served as a deputy campaign manager for Obama’s 2012 reelection effort and as executive director for the Democratic National Committee during his first term.

During Obama’s first term, she was an attendee of regular strategy meetings where Obama’s brain trust prepared for the 2010 midterms and the 2012 reelection campaign.

More recently, she helped to lead an early 2019 Democratic effort to create a new for-profit data exchange to allow for greater information sharing among Democratic campaigns and affiliated groups, an effort party leaders see a crucial for catching up with the Republican data program.

O’Malley Dillon later served as the presidential campaign manager for former congressman Beto O’Rourke, D-Texas, relocating to El Paso. After O’Rourke’s campaign ended, she volunteered as a campaign adviser for Biden before the Nevada caucuses, and then continued on as an informal adviser to senior Biden campaign officials in recent weeks.

O’Malley Dillon will work out of the campaign’s Philadelphia headquarters.