Dual Class Certificate Manager:
Learning the Dual Class Certification Skill is a great thing.
That's why going back on it will burden your soul. That's why you need the special power of an herb to seal a skill that you have learned.
The price of the herb is 20 million Adena. I already have the herb, so you just need to pay for it.
If you cancel the certification, your current certification status disappears, and so do all certificates and stamps in your inventory that you haven't used yet. So... what do you want to do?