Donald J. Trump, who has again reorganized his staff in an effort to right his faltering campaign, will receive his first classified briefing on Wednesday since becoming the Republican presidential nominee, according to a person briefed on the meeting.

The meeting comes as Mr. Trump’s campaign appears to be going through another upheaval, as some of his top advisers have urged the candidate to dig in and prepare for a prolonged and aggressive fight for the presidency and amid questions over his campaign chairman’s ties to a pro-Russian political party in Ukraine.

Gov. Chris Christie of New Jersey, who leads Mr. Trump’s transition team, and retired Lt. Gen. Michael Flynn, who formerly led the Defense Intelligence Agency, will also attend the briefing.

According to ABC News, which first reported on the timing of the briefing, it will take place at the F.B.I. field office in Manhattan, which can accommodate the appropriate security needs.