Army Lt. Col. Alexander Vindman, the top Ukraine expert on the National Security Council, told members of Congress that he tried to edit a White House log of a July call between President Donald Trump and Ukraine's president to include details that were omitted, one lawmaker present at the testimony and another source familiar with it confirmed to NBC News.Vindman testified in a closed-door deposition before House impeachment investigators that the attempted edits were to reflect Trump mentioning possible recordings of former vice president Joe Biden discussing corruption in Ukraine and Ukrainian President Volodymyr Zelenskiy mentioning Bursima, the company who had hired Biden's son, Hunter, the sources said.The July 25 phone call between Trump and Zelenskiy is at the center of an impeachment inquiry being conducted in the House of Representatives. Critics say the alleged pressure on the Ukrainians amounted to Trump abusing his power for political gain in the 2020 presidential election.Vidman's testimony was first reported by The New York Times.The White House in September released a transcription memo about the phone conversation. But there are several points in that document that contain ellipses._Download the NBC News app for breaking news and politics_At the time it was released, the White House noted that the summary of the call was not a verbatim transcript and that it represented a record of "the notes and recollections of Situation Room Duty officers and National Security Council policy staff" who listen to official conversations.Vindman said he listened in on that call, and in his opening statement prepared for delivery said he went to the National Security Council lead attorney over his concerns, and that "I did not think it was proper to demand that a foreign government investigate a U.S. citizen, and I was worried about the implications for the U.S. government's support of Ukraine."The Times reported that Vindman tried to change the reconstructed transcript made by the White House staff to reflect the omissions. But while some of his edits appeared to have been successful, he said, those two corrections were not made.Vindman did not testify to a motive behind the editing process, and it is not clear why some of his changes were not made, while others he recommended were, the newspaper reported.Trump and his defenders have denied that there was any quid pro quo related to held-up aid to Ukraine and actions by that government. Trump has described the call as "perfect" and said he did nothing wrong, and has attacked the impeachment inquiry as a "witch hunt."The House impeachment inquiry was launched after a whistle-blower complaint was withheld from members of Congress.That complaint says that White House officials were so concerned about what the president said in the July call with Zelenskiy that they intervened to "lock down" the transcript of the conversation.The identity of the whistle-blower remains secret.