Only the person who bought a ticket can resell it. If your Humanitix ticket was purchased on your behalf by another person, they will need to list your ticket for public resale or generate a private resale link for you.
You can send them the following instructions:
Search for your order confirmation email sent to your email address.
Click the manage order button
Select the resale tab and choose sell tickets
Select the ticket you want to resell
List the ticket for public resale, or, generate a private link and share this unique link