How to change enchantment on tools?

[prime pewter]

I got Extra Drop and Swift Swing on my gold pickaxe. I want to change the Swift Swing one for other enchant. I used the Add option and I kept getting upgrade on Swift Swing. So I need to use the Upgrade option?

Just want confirmation because the Upgrade one cost so much T__T

[tawny hamlet]

No, it will upgrade the skill if it rolls duplicate, just have to keep rolling to get a new enchant