President Trump launches his push for tax reform. Plus, Cortana and Alexa teaming up! Why Microsoft and Amazon are letting their A.I. assistants work together, and could it be the start of a trend. Designer and former Hills star Kristin Cavallari stops by our Santa Monica studios to show off her new jewelry line. New Uber CEO Dara Khosrowshahi has a full plate as he starts at the ride hailing giant. And, how to make sure your donation is having a positive impact for victims of Harvey in Texas. Those stories and much more on today's Closing Bell.