How do i start CWK exchange quest?

You have to earn the trust of the Ninja Clan by giving them the Map of Phantom Forest, which Jack Barricade will give you as a quest reward.

Vovez, you're 7x, right? The quest above isn't activated yet if you haven't completed Subani's Legacy, Elpam's quests, Cleaning up the Streets, and Finding Jack, as well as the Phantom Seed quest.

Edit: Stereo beat me to it. :p