He’s not “reversing” anything. He didn’t promise to deport dreamers. He said repeatedly that his main focus would be illegals who have committed other crimes, especially drug or human trafficking, rape, murder, etc.
“We will immediately terminate President Obama’s two illegal executive amnesties in which he defied federal law and the Constitution to give amnesty to approximately five million illegal immigrants, five million.”
— Donald Trump, August 31, 2016