Donald Trump isn’t the president yet, the incumbent president expressed on Monday, telling the press ahead of a foreign trip “there is one president at a time.”President Barack Obama kicked off a news conference Monday by hailing his team’s transition efforts and suggested his staff is ready to kick it into high gear.“As I discussed with the president-elect on Thursday, my team stands ready to accelerate in the next steps that are required to ensure a smooth transition, and we are gonna be staying in touch as we travel,” Obama said in his opening remarks before taking questions in the White House Briefing Room before departing for a foreign trip to Greece, Germany and Peru.“I remember what it was like when I came in eight years ago.