The below is attributable to Spokesperson Heather Nauert:
Secretary Michael R. Pompeo spoke with UN Special Envoy for Syria Staffan de Mistura and discussed the Special Envoy's progress on convening a constitutional committee. The Secretary thanked de Mistura for his efforts in de-escalating the military conflict and re-invigorating the political peace process. The Secretary also thanked de Mistura for his more than four years of service on behalf of the Syrian people, as well as his many years of UN service around the world.
Source: US Department of State