Exchange officer

An exchange officer is an individual, usually a commissioned military officer, attached to the armed forces of another nation's military on a temporary or semi-permanent basis. Several governments and armed forces have participated in officer exchange programs in the interests of sharing knowledge, techniques and tactics from different training backgrounds and perspectives, and in order to foster greater cultural understanding.
 * ''Exchange officers have appeared in Star Trek and its numerous spinoff fan productions.

Federation-Klingon
The Federation-Klingon Officer Exchange Program was established in the 2360s as a way of improving relations between the United Federation of Planets and the Klingon Empire. Officers who serve in the program may be awarded the Federation-Klingon Officer Exchange Program Medal.

Commander William Riker of the Enterprise-D volunteered for the program and was posted aboard the, a Klingon Bird-of-Prey. A Benzite, Mendon, was posted aboard the Enterprise-D as part of the same program. 

Kurn, second son of Mogh, later joined the program as a way of meeting his brother Worf. Worf, in turn, served as an exchange officer in the Klingon military on several occasions, such as under Gowron during the Klingon Civil War of 2367, as a first officer and even captain , while retaining his Starfleet rank and commission.

The Klingon spy J'Dan used the program to give information on the Enterprise-D to the Romulans. 

Half the Klingon crew of the exchanged with half the Starfleet crew of the USS Phoenix-X (NCC-75948) as an effort to support relations. In late 2378, when the exchange was scheduled to conclude, the exchanged crews of both sides were so involved and content in the others' respective ships that they opted to extend the exchange schedule for as long as possible. (: "Betrayal and Honour", "Destiny's Revenge, Part I")

Federation-Romulan
The Federation-Romulan Officer Exchange Program between the and the Romulan Star Empire allowed both governments to exchange officers of their respective fleets. This previously impossible program was made possible due to the peace between Romulus and the Federation after the Shinzon incident of 2379. Trevak was a Romulan member of the program assigned to the USS Remington (NCC-86753) as its first officer. (: "Inceptum II")

Other notable exchange officers

 * Jadzia Dax
 * Matthew Kent
 * Red
 * T'Pol