In the L2 site, it says...
Second Awakening of Dualclass
Dualclass with complete Awakening can Awaken again and change the class via Dual Class Master Raina in Talking Island Village.
To change dualclass your character needs to have a class cloak of dualclass in the inventory.
You’ll also need to pay a certain amount of adena for changing dualclass.
It’s impossible to choose the class which matches the main or dualclass your character has at the moment at the second Awakening.
At the second Awakening, the dualclass level will be changed to 85, all the skills learned will be deleted, including certified ones, the character will get the certificates spent on the skills back into their inventory.
That it means that I can change my Dual, from ISS to Archer ?