Sorry for the short notice on this one, it was announced this morning but I just found out now.

8 PM Eastern / 5 PM Pacific, from the Oval Office. Biden speaking, presumably about the Trump assassination attempt.

https://www.nbcnews.com/politics/joe-biden/biden-oval-office-address-sunday-evening-trump-shooting-rcna161790

Video here of the earlier conference, still looking for the Oval Office speech.

https://www.youtube.com/live/zhQ2SshESqA#t=42m25s

Oval Office speech here:

https://www.youtube.com/live/Qji7y15tsOE#t=1h0m10s