No class can queue for anything other then what they are, DD, Tank, healer. However, Archanist, has two different paths it can take for jobs, Summoner and Scholar. Archanist and Summoner queue up as DPS, but Scholar queues as a healer. Thats the closest you'll get.

The reason for this though, is that unlike most other MMOs, one character can learn all classes and all jobs, thus YOu simply need change your class or job to queue as something else.

Hope this helps you.