Quote Originally Posted by Diana_Pepper View Post
"Players in possession of a Zodiac Weapon Zeta may exchange this weapon for items required to progress through a certain quest. Although the Zodiac Weapon Zeta will be lost upon exchanging it, players may purchase replicas should they choose to preserve its appearance via glamours."

In regards to this, does this mean I can use this exchanged item to swap over to a different relic? (I have Dragoon's Zeta but I now main Monk and like to switch)
yes you can use any Zeta. I believe this was asked in some letter/whatever quite recently and its to help the new jobs specifically who couldn't have one on their job.