On Monday, the directors of the FBI and National Security Agency testified before the House Intelligence Committee.
During the hearing, the House Intelligence Chairman asked Mike Rogers if votes tallies in key swing states were changed and Rogers confirmed that there's no evidence that any votes have been compromised in the election.
House Intelligence Chairman Devin Nunes listed several key swing states -- Michigan, Wisconsin, Pennsylvania, Florida, North Carolina and Ohio -- and asked Rogers if there was any evidence that vote tallies were changed.
Source: http://edition.cnn.com/2017/03/20/politics/comey-russia-hearing-trump-obama-what-learned/
I'm just curious as to what would happen if they found evidence that vote tallies were actually changed. Since the electoral college had already voted for the winner and the President had already inaugurated, what would happen since the Constitution doesn't state anything (as far as I recall)?