CONCORD, N.H. — Former vice president Joe Biden's campaign is shaking up its top staff echelon, giving greater responsibility to adviser Anita Dunn as it seeks to signal a new phase of the campaign following a disappointing fourth-place finish in Iowa that has rattled donors and supporters.

The shift was announced in an email sent out by campaign manager Greg Schultz and longtime Biden adviser Steve Ricchetti. It described Dunn as taking on “an expanded role.”

The move, first reported by the New York Times and confirmed by two Biden advisers, appeared designed to calm donors and skittish supporters, but it was unclear how much it would actually change the internal operations. Dunn has been heavily involved in the campaign from the start.

She was also deeply involved in preparing Biden’s emerging campaign in 2015 before he decided not to run for president that year. Dunn has played a role in debate preparations from the start of this election cycle, and her responsibilities have grown as the year progressed.

The two Biden advisers, who spoke on the condition of anonymity to discuss internal campaign strategy, downplayed the significance of the move, with one saying the campaign simply needed added capacity as it moves toward the Nevada caucuses on Feb. 22 and the South Carolina primary a week later.

They are followed by Super Tuesday on March 3, a potentially decisive point in the campaign when more than a dozen states will cast primary votes.

Dunn’s elevation could help alleviate some staff tensions within the Biden operation as it seeks to rebound from Iowa. People close to the campaign have described at least two internal factions, with Biden’s longtime advisers — including Ricchetti and aide Mike Donilon — at odds with some younger operatives, such as Schultz and deputy campaign manager Pete Kavanaugh.

Dunn is seen as a neutral arbiter who could help ensure the different groups are not clashing as the campaign attempts to regain its footing.

The topic came up several times during a Biden campaign briefing with reporters on Friday afternoon. The campaign insisted none of the Biden advisers on the call be identified.

“We’re expanding her role a little bit to utilize her talents,” one of the advisers said. “This is not an overhaul of our campaign structure. It’s frankly not a dramatically different role for her.”

The adviser added, I understand the tendency to overanalyze and ascribe meaning to a personnel change at this stage in the race. But this is not bringing in someone new, this is not restructuring. This is just giving a slightly broader portfolio in the campaign to someone who has been deeply involved from the outset.”

But when asked who is running the campaign — Dunn, Schultz or someone else — the adviser declined to answer, saying only, “The person in charge of the campaign is Joe Biden.”

Biden’s fourth-place Iowa finish — which came after he had led the Democratic field in national polls for nearly a year, and which the candidate himself called a “gut punch” — has prompted rivals, voters and party officials to wonder if the former vice president will change his approach, messaging or staff.

A second adviser on the call insisted the campaign was not struggling financially, and they said Biden had enjoyed the best week of online fundraising since the start of the campaign.

“We have the resources we need to run our race,” one of the advisers said. “We are not running out of money.”