https://thepostmillennial.com/breaking-joe-biden-calls-kamala-vice-president-trump-in-flub-filled-big-boy-press-conference

Also with Zelensky standing right there, Biden called him President Putin.

Biden responded, "I wouldn't have picked Vice President Trump to be vice president if I didn't think she was not qualified to be president. So, let's start there."

In the case with Zelensky, Biden said, "And now I want to hand it over to the President of Ukraine, who has as much courage as he has determination. Ladies and gentlemen, President Putin."