the decision to send ivanka trump to south korea for the closing ceremony for the olympic games not sitting well with the white house. including the chief of staff. the stakes were considered far higher than a typical closing air mon ceremony. a seasoned diplomat is retiring as we have learned overnight. let's go to seoul and cnn's ivan watson. >> reporter: christine, this diplomat's name is joseph yun. he is a specialist dealing with north korea and former ambassador and more than 30 years with the state department. he says it is his choice to step down. the state department put out a message saying secretary of state rex tillerson regretfully accepted mr. yun's resignation letter. also stressed that the u.s.