Who in the desert do i talk to...

to change my secondary profession to an elementalist? I'm not quite sure and i thought i've looked in a lot of places but to no avail i still cannot find who

There's only three possible places. Hero's, Seekers, Or Gorge.

You have to get the quest from Vanyi first and then complete the Elementalists Path quest. After that any of the "path" quest givers will allow you to change your profession to any of those you've completed the "path" for or for your original profession.

Once you've Ascended and have gotten to Droknar's Forge, talk to Vanyi by the storage. Take the Hero's Journey quest and return to Hero's Audience. Talk to Cembrien and get the Elementalist's Path. From there go to Augury Rock and head into the Prophet's Path and find and slay the Kree Minotaur (warrior boss). Usually found running around the large sand dune to the east of Augury Rock.

Good luck!