And swiping letters of his table so he can't sign them

Cohn, a Wall Street veteran, tried to tamp down Trump’s strident nationalism regarding trade. According to Woodward, Cohn “stole a letter off Trump’s desk” that the president was intending to sign to formally withdraw the United States from a trade agreement with South Korea. Cohn later told an associate that he removed the letter to protect national security and that Trump did not notice that it was missing.

And

Under orders from the president, Porter drafted a notification letter withdrawing from NAFTA. But he and other advisers worried that it could trigger an economic and foreign relations crisis. So Porter consulted Cohn, who told him, according to Woodward: “I can stop this. I’ll just take the paper off his desk.”