Former Vice President Joe Biden is shaking up his presidential campaign as he promotes longtime advisor and Democratic strategist Anita Dunn.

The decision was announced in an email to Biden campaign staff, according to NBC News.

"Most of you already know Anita or may have seen her hanging around communications – she will be working closely with us on campaign strategy and overall coordination on budget and personnel as we build a bigger campaign for the next phase," the email read.

Dunn, a partner at advertising juggernaut SKDKnickerbocker, has been a surrogate for Biden since the start of his run for president. She served key roles in President Barack Obama's White House and campaigns after spending decades working for top Democratic figures such as former Vice President Al Gore, and Sens. Tom Daschle and Bill Bradley.

The decision to give Dunn more responsibilities comes as the campaign is at a crossroads. Biden underperformed rivals Sen. Bernie Sanders, Pete Buttigieg and Sen. Elizabeth Warren in the Iowa caucus, although that contest's results were marred by discrepancies in the count.

In New Hampshire, which holds its primary Tuesday, polls show Biden on track for another disappointing finish, according to a RealClearPolitics polling average.

Still, Biden continues to lead in most polls nationally, ahead of Sanders, Warren, former New York Mayor Mike Bloomberg and Buttigieg.

Top Biden advisors said in a call with reporters before a debate in New Hampshire on Friday night that Dunn's new role should not be seen as a "dramatic shift" because she held a senior position prior to her promotion, NBC reported.

Since his disappointing showing in Iowa, people in Biden's orbit have been privately questioning the campaign's tactics. There are now serious doubts about whether Biden's campaign could survive what appears to be a likely loss in New Hampshire and if it were to underperform in the Nevada caucuses and South Carolina primary, which are scheduled for Feb. 22 and 29, respectively. Biden holds a slight edge in the Nevada polling average, while he holds a double-digit edge in the South Carolina average.

"The one thing that's wrong with the Biden organization is that the staff is not preparing him with the kinds of things he has to face," Bernard Schwartz, a longtime investor and Biden donor, told CNBC.

Biden's struggles are also linked to his fundraising woes. His campaign went into 2020 with less cash on hand than many of the other contenders. In the aftermath of Iowa, he canceled nearly $120,000 in South Carolina ads, according to tracking firm Advertising Analytics, and added to his TV bookings in Nevada.

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Here's the text of the email that was sent to Biden staff, according to NBC News.