Real World article
(written from a Production point of view)

Mercedes is the last name of the actress who appeared as a J'naii pilot in the Star Trek: The Next Generation fifth season episode "The Outcast" in 1992. She only worked in the sickbay scene and replaced fellow actress Tara Christie who previously played the same character in the scenes aboard the shuttle. Mercedes received no credit for her appearance and was identified by the call sheet for the day of filming.