Cross-campaign unique secondaries

How does this work?

I have a Tyrian warrior who's still slogging through Maguuma Jungle, but HAS completed Sunspears in Kryta and can go to Elona. I want to switch 'em to /Dervish. Do I have to both do Tyrian ascension AND the Command Post quests (to get Elonian profession changer), or just the post quests?

my advice would be to simply go through your campaign, and from the moment you're ascended, travel to the temple of balthazar (the PvP town) and talk to the profession guy there. He offers all the secondaries you have access to.