Maybe it was just the private reports given to the media that were modified.
"Election night returns are unofficial and in general do not come from the election officials.
These are private reports that are given to the media and the media publishes them.
And no election professional, whether it be an election administrator, whether it be a candidate or whether it be lawyers who handle the election process rely on the election night returns because they know that the election night returns have a huge margin of error because of typographical errors or the oral transmission that happens when results are transmitted over the phone lines."
https://www.elections.ny.gov/NYSBOE/News/MeetingMinutes/CCTranscriptions12152009.pdf