“President-Elect Trump, as well as Don, Eric, and Alan are committed to ensuring that the activities of The Trump Organization are beyond reproach, and that the Organization avoids even the appearance of a conflict of interest, including through any advantage derived from the Office of the Presidency,” Ms. Dillon wrote in the six-page document, referring to Mr. Trump’s two oldest sons and Alan Garten, the chief legal officer at Trump Organization.

But that same day, Mr. Trump made clear he was aware that he had a legal exemption that provided him considerable flexibility to decide for himself what would be permissible.

“I have a no-conflict-of-interest provision as president,” Mr. Trump said. “It was many, many years old, this is for presidents. Because they don’t want presidents getting — I understand they don’t want presidents getting tangled up in minutia; they want a president to run the country. So I could actually run my business, I could actually run my business and run government at the same time.”

Bobby R. Burchfield, a lawyer who serves as the ethics adviser to the Donald J. Trump Revocable Trust — which technically owns the family hotels and other properties that are now managed by his sons — said on Friday he is examining the matter.

“We are looking at the situation” he said. “The president, the Trump Organization and I are committed to ensuring that this is done in compliance with the ethics standards.”

Mr. Trump himself, in late August, at the end of the Group of 7 summit in France, first confirmed publicly that the Trump family resort in Doral, Fla., was being considered for the June 2020 gathering.

“Having it at that particular place, because of the way it’s set up, each country can have their own villa, or their own bungalow,” Mr. Trump said in August, before continuing later in his remarks that “I think it just works out well.”