An employee of former President Donald J. Trump changed his grand jury testimony in the documents case after the Justice Department raised questions about whether his lawyer had a conflict of interest in representing both the employee and a defendant in the case, prosecutors said in a court filing on Tuesday.

The prosecutors working for the special counsel, Jack Smith, had asked for a hearing to address the fact that the employee, who is a possible witness in the case, was represented by the lawyer Stanley Woodward. Mr. Woodward also represents two other possible witnesses and one of the co-defendants, Walt Nauta, a personal aide to Mr. Trump.

The employee was not named in the court filings but was identified by people familiar with the matter as Yuscil Taveras, an information technology worker at Mr. Trump’s private club and residence in Florida, Mar-a-Lago.

Mr. Trump was charged in June with mishandling classified documents he had taken with him upon leaving the White House and obstructing the government’s efforts to reclaim them. Mr. Nauta was charged alongside Mr. Trump, and prosecutors filed additional charges in July, accusing Mr. Trump of telling Carlos De Oliveira, the property manager at Mar-a-Lago, that he wanted security camera footage there to be deleted.

Mr. De Oliveira was also charged in the superseding indictment, which cited testimony from a witness who appeared to be Mr. Taveras. Mr. Taveras has not been charged in the case.

Mr. Woodward’s fees have been paid by Save America, the political action committee aligned with Mr. Trump. The PAC was seeded with small donations from Mr. Trump’s supporters, who responded to his calls to help him prove what he falsely claimed was widespread fraud in the 2020 election. No evidence of such fraud ever surfaced. Trump advisers have insisted that there is no connection between any witness’s testimony and payment of their legal fees.

Mr. Taveras originally told the grand jury he did not recall having any conversations regarding security footage from Mar-a-Lago that the government had subpoenaed in 2022 as part of its investigation into Mr. Trump’s retention of classified documents including national defense material. Mr. De Oliveira made similar statements.

According to the government, both statements were false.

After the government raised questions about Mr. Woodward’s representation of multiple people who could be connected to the case, the prosecutors said in their filing on Tuesday, the chief judge overseeing the federal grand jury in Washington, James E. Boasberg, offered Mr. Taveras a federal public defender to “provide advice” about potential conflicts.

“On July 5, 2023, Trump Employee 4 informed Chief Judge Boasberg that he no longer wished to be represented by Mr. Woodward and that, going forward, he wished to be represented by the First Assistant Federal Defender,” the filing said, referring to Mr. Taveras. “Immediately after receiving new counsel, Trump Employee 4 retracted his prior false testimony and provided information that implicated Nauta, De Oliveira, and Trump in efforts to delete security camera footage, as set forth in the superseding indictment.”

Mr. Woodward declined to comment. A Trump campaign spokesman and a Trump Organization spokeswoman did not respond to a request for comment.

But Mr. Taveras’s revised statements about Mr. Nauta and Mr. De Oliveira appeared to have been key to the decision by Mr. Smith’s team to indict Mr. De Oliveira in late July in connection with alleged efforts to find ways to delete the security footage.

After the government raised questions about whether Mr. Woodward had a conflict of interest, the judge in the case, which was brought in Florida, Aileen M. Cannon, asked Mr. Woodward whether it was legitimate to have two grand juries in a single case.

Mr. Woodward said he thought it was not, and asked the judge to consider striking Mr. Taveras’s testimony for that reason. Judge Cannon has not yet ruled on that matter, but if she does ultimately move to strike Mr. Taveras’s testimony, it could hamper the superseding indictment brought by the government against Mr. De Oliveira and Mr. Trump.

Mr. Woodward’s situation in Mr. Trump’s legal cases is not unique. Other lawyers for people connected to the documents case represent multiple witnesses or even defendants.

The government is separately investigating the payment of lawyers by Save America. The PAC has settled more than $21 million in legal fees for Mr. Trump and several witnesses in the case since January.