WASHINGTON (AP) — After nearly a near year of careful planning, organizers of the Democratic National Convention are in a mad dash to accommodate a new nominee, a re-crafted program and a highly compressed deadline to pull everything off as though this was the plan all along.

With President Joe Biden now out of the race and Vice President Kamala Harris pursuing the party's nomination, a dramatic role reversal for the two is likely to play out before a nationally televised audience when around 5,000 delegates, 12,000 volunteers and 15,000 media members gather for four days in Chicago starting Aug. 19.

Harris is banking on introducing her vice presidential pick to the country and standing at center stage to accept her party's nomination. Biden — who until mere days ago thought he'd be the one getting the nod — will have a more peripheral and ceremonial role akin to the treatment of second-term presidents set to leave office.

He will still give a speech and have his achievements feted, but the whole thing will require a delicate political balance between the president and his No. 2.

"If it's a Biden-Harris reelection convention, it's all about doubling down on the great accomplishment. The challenge, obviously, will be how to sort of bank that, but also talk about the future," said William M. Daley, a former Obama White House chief of staff whose father and brother were Chicago mayors.

There have occasionally been tensions, or at least struggles with political messaging and tone, as vice presidents campaign to succeed a president — like in 2000, when Bill Clinton was in office and Al Gore was seeking the White House. Clinton left the convention after offering a triumphant review of his accomplishments on the first day, but prominent party leaders urged him to more definitively cede the spotlight to his vice president going forward, citing the Monica Lewinsky scandal that prompted the president's impeachment.

Then-Sen. John Kerry of Massachusetts, who would be the Democratic nominee himself four years later, said of Clinton: "We may need to get the Jaws of Life to pry him free from the thing -- but we've got to pry him free."

As for Biden's situation this year, "there are people in the party that would have rather seen something different happen. The question is can this be subsumed to an overarching unity message," said Julia Azari, a political science professor at Marquette University who is co-authoring a book on the vice presidency and political parties.

A convention helmed by Harris would nonetheless make history as Democrats become the first major party to nominate a woman of color for president.

"It lights a fire under national Democrats. It's an added level of history," said Christian Perry, political director for Chicago Mayor Brandon Johnson. He added that Harris would break more barriers in a city that produced a series of history-making Black Democrats, from the Rev. Jesse Jackson to Barack Obama.

The vice president isn't her party's nominee yet, but an Associated Press survey of delegates to the convention has revealed that the vice president has the support of well more than the 1,976 delegates she'll need to win on a first ballot.

"I think it'll be a celebratory mood," said Bruce Thompson, a member of the convention rules committee. "There's been way too much gallows humor in the Democratic Party over the last month. And now we have this confidence and this energy."

Like Biden, Harris could be expected to use the convention to promote the administration's policy accomplishments, while decrying Republican President Donald Trump as a threat to democracy.

But other aspects of the campaign are shifting profoundly — from fundraising and travel schedules to how Harris targets key states and the personal advisers closest to her. The vice president's "Harris for President" logo in blue and red does feature lettering similar to the original Biden-Harris reelection insignia, at least.

The convention's background music could also reflect a fresher vibe.

In the first appearances of her nascent 2024 presidential campaign, Harris' soundtrack has featured Beyoncé's hit "Freedom." Biden's events leaned more toward working-class-themed ballads by the likes of Bruce Springsteen.

The Chicago convention will have different themes each night, such as economic growth or national diversity. In addition to Biden, there will be addresses from White House alums Barack and Michelle Obama and Bill and Hillary Clinton.

Before Biden bowed out of the race, he and his family gathered at Camp David to pose for famed photographer Annie Leibovitz for photos to be used at the convention. They'll still be used — but likely in a more retrospective way.

For all the upheaval to the presidential race, organizers say actual convention logistics won't change all that much — highlighting how the quadrennial gatherings are as much about a party partying as they are about fortifying candidates.

"Our mission remains the same," said convention chair Minyon Moore.

Party staff began occupying the United Center, normally home to the NBA's Bulls and the NHL's Blackhawks, on June 25. Construction to remake the arena to better meet the convention's needs has been underway for more than a month, with nearly as long still to go. The convention logo still reads "CHICAGO" over the city's signature four-star insignia and "DNC 2024." The slogan remains: "Our future is created here."

"There's not a lot in the actual hall that has to move around because you're taking one out and putting the other in. It's all somewhat neutral," Daley said. "The stage and all that, is all set, if it's Biden or it's Harris or who walks out."

Also unaltered are plans for widespread demonstrations protesting the Biden administration's strong support for Israel in its war with Hamas.

"His decision doesn't change the policies of Democratic Party leadership, specifically their support of the genocide in Palestine," the Coalition to March on the DNC, which represents activist groups planning protests, announced after Biden left the race.

Azari said Democrats may be hoping to re-create the last time the Democrats held a Chicago convention in 1996, when there were no significant protests, the party was mostly unified behind Clinton and the lasting image was of Hillary Clinton and others dancing the Macarena.

"The '96 convention is what they're aiming for," Azair said, "where the biggest story is gonna be people dancing badly."