alt Hacker NewsA president can not make a law, only sign them into existence. He can also direct enforcement or lessen it.
As far as I understand, the Schedule of Cannabis is written into the US Code. So Congress would need to amend it.
https://uscode.house.gov/view.xhtml?req=granuleid:USC-prelim...
It's under the purview of the executive branch to determine drug scheduling
> The term "list I chemical" means a chemical specified by regulation of the Attorney General ... until otherwise specified by regulation of the Attorney General