Trump-Kim summits: From Singapore to Hanoi, what has changed?

The same leaders, but different venues, travel plans and expectations – U.S. President Donald Trump and Democratic People's Republic of Korea (DPRK) leader Kim Jong Un are going to meet for the second time in eight months. How is the Hanoi summit, scheduled for February 27-28, different from the Singapore meeting that took place on June 12 last year?