I don't even understand why you are asking that question, and what you are suggesting.
Do you believe that she did not have access to classified info?
This is what she said at the hearing about what she told Don McGahn, the WH counsel:
"I told them again that there were a number of press accounts of statements that had been made by the vice president and other high-ranking White House officials about Gen. Flynn's conduct that we knew to be untrue.
And we told them how we knew that this – how we had this information, how we had acquired it and how we knew that it was untrue."
The day before that meeting in the WH she was briefed by the FBI, who had interviewed Mike Flynn the day before that.
Sally Yates Provided a Helpful Timeline of the Mike Flynn Saga
This is from the transcript of her hearing:
WHITEHOUSE: Following the Comey line, the director testified a few days ago in the full committee that the FBI had interviewed Mr. Flynn a day before, or two days before, your meeting at the White House, and you've just testified that you had told the White House counsel that the FBI had interviewed Flynn and he'd asked -- McGahn had asked, how'd he do?
YATES: Right.
WHITEHOUSE: Did you have the 302 with you when you were in the White House? Did you show it to White House counsel? And had you seen it at the time you went up to the White House?
YATES: No. The FBI had conducted the interview on the 24th. We got a readout from the FBI on the 25th, a detailed readout specifically from the agents that had conducted the interview.
But we didn't want to wait for the 302, because we felt that it was important to get this information to the White House as quickly as possible, so we had folks from the national security division who spent a lot of time with the agents, not only finding out exactly how the interview went but how this impacted their investigation.
WHITEHOUSE: So did you take that summary with you? Do you have any document with you that described the FBI interview of General Flynn?
YATES: At the time that I was there, I had notes that described that interview, as well as the individual that was with me -- the senior career official from the national security division -- had been part of all of those discussions with the FBI.
Full transcript: Sally Yates and James Clapper testify on Russian election interference
http://wapo.st/2po7EVI
So it seems that she probably learned it from the FBI, because the day after they briefed her she went to the WH.