(Reuters) - President Joe Biden will receive the official nomination from fellow Democrats for a second term in a virtual vote as planned in late July, ahead of the party's national convention, despite calls for him to step aside, four people involved in the process told Reuters.

Democrats and Republicans typically use their national conventions to officially nominate their candidates, but Biden will be nominated weeks before his party gathers for its Democratic National Convention in Chicago on August 19 - a plan that was announced long before Biden's shaky June 27 debate.

Exactly how the early nominating process will work is unclear, however, said the state party officials and national Democrats interviewed for this story.

Reuters spoke to more than 20 of the 4,500 delegates who will be involved in the nomination. Eight told Reuters they either had not heard about what senior Democrats have described as a "virtual roll call" or they had not heard any details on it recently. One said the only communication they had received lately had been about the in-person Convention.

UNDER PRESSURE

Biden, 81, is under continued pressure and scrutiny from some lawmakers, donors and activists to drop his reelection campaign in the wake of his disastrous presidential debate performance, which renewed questions about his mental fitness.

But Biden campaign officials said they expect that Saturday's assassination attempt on Republican rival Donald Trump will lower the pressure on Biden to step aside.

Biden insists he is not going anywhere and says he is best equipped to beat Trump.

Pushing forward with a virtual nomination could speed up Biden's formal nomination and stave off potential challengers to his candidacy. But the confusion surrounding the virtual nomination process reflects the chaos within the party, as senior leaders focus on salvaging Biden's candidacy, sources said.

EARLY NOMINATION PLANS

The early nomination was needed to deal with an Ohio law that could have kept Biden's name off ballots in the state if he wasn't nominated by Aug. 7, prior to the convention in Chicago.

Democrats are still moving forward with the plan even though Ohio Gov. Mike DeWine signed a bill in late May to secure Biden's spot on the state's ballot after it passed the Republican-controlled state legislature.

An online or virtual vote means no chance of a live convention floor battle in Chicago that could embarrass Biden and throw the campaign into chaos.

HOW WILL IT WORK?

Many of the details will be determined on July 19 and 21 when the party's convention rules and credentials committee meet, respectively.

Any virtual nomination process is likely to happen within days of those meetings, officials said.

Some officials with the Democratic National Committee and the Biden campaign said to expect something similar to 2020, when the COVID pandemic forced the party to hold a virtual roll call that featured state officials backing Biden against the video backdrop of American landscapes.

Others said the early nomination process will be much less dramatic, with delegates filling out online voting forms and a bureaucratic marking of Biden's nomination without a roll call.

Either way, Democrats plan to do a traditional roll call at the August convention with a mix of pre-recorded messages and live action, even though the formal nomination will have already taken place.

4,500 DELEGATES DECIDE

In 2024, there will be an estimated 4,532 delegates at the Democratic National Convention, including 3,788 pledged delegates and 744 "automatic" delegates -- more commonly known as superdelegates.

To win the Democratic nomination, a presidential candidate needs to receive the support of a majority -- or roughly 1,895 -- of the pledged delegates in the first roll call. If not, the superdelegates - who are free to vote for whoever they like - will join and help decide in the second roll call.

During the party's primary election, where Biden faced no serious opposition, he secured the support of some 3,900 delegates, significantly more than needed.

Pledged delegates are expected to support Biden but there are differing opinions on whether they are bound to support him.

Democratic National Committee officials have been making calls to delegates to take their temperature in recent days to identify any potential problems, officials told Reuters.

The delegates are expected to be given three options: support Biden, uncommitted or leave blank, according to party officials. All the delegates Reuters spoke to said they plan to support Biden.

On Thursday, Biden was asked about concerns that delegates will defect from Biden.

"Obviously they're free to do whatever they want, but they -- I get overwhelming support," Biden said. "It's not going to happen."

WHAT IF BIDEN STEPS DOWN AFTER NOMINATION?

If Biden steps down after the official nomination, the 435 members of the Democratic National Committee would choose a new candidate, in a special session.

The members are divided roughly equally between men and women as well as various constituency groups including labor leaders, LGBTQ representatives, and racial minorities.

Of the total, 75 are appointed at-large by the chair, while the rest are elected in their respective states.

(Reporting by Jarrett Renshaw and Stephanie Kelly; additional reporting by Andrea Shalal and Jeff Mason; Editing by Heather Timmons and Diane Craft)

By Jarrett Renshaw and Stephanie Kelly