I bought a tier 2 Chaos jewelry bracelet at the Mar and Sar. I thought I could add/replace gems on my own, but it seems not. I see on the Wiki page that I would need a certificate to unlock it to tier3. And it looks like I would need a certificate from Reim to change the gems/materials. Or is this something a merchant could do if I had the gems?

So, my question is how do you change the gems on a Chaos jewelry?