You are able to "gift" the license to anyone. Then the monetary transaction is handled by Paypal or any service of your choice. The receiver of the "gift" (=the license) must have a registered account with Line 6. If not you won´t be able to gift it.
Go to "Hardware and Software" under your profile, and then to Purchase History. You are supposed to find the "gift" option next to or under the purchase info (for your purchase of the Helix native License that is).
PM me if you want to sell it, I´m looking for a Native license.