What is another word for "diplomatist"?

Roget's Thesaurus (1911) lists these synonyms for "diplomatist": advocate, agent, ambassador, apparitor, arbitrate, arbitration, arbitrator, attache, attorney, auctioneer, bag, bagman, bailiff, bargain, bearer, bellman, boy, broker, business, cable, carrier, charge, chore, clerk, commercial, commissary, commission, commissionaire, commissioner, committee, compromise, consignee, consul, corps, correspondent, courier, crier, curator, dak, delegate.