On January 5, following a briefing by IC leadership on "Russian hacking" during the 2016 Presidential election, President Obama had a brief follow-on conversation with Vice President Joe Biden, FBI Director Jim Comey, National Security Advisor Susan Rice and Deputy Attorney General Sally Yates in the Oval Office.
This is when they formulated their plan to go after General Flynn.
Something not-so-well known is that Chief Justice John Roberts was on speaker phone during this meeting.