Whether you can resell your ticket(s) or not is dependent on the event in question. 

You can check if there is an official resale option available for your tickets by going to your confirmation email and clicking on Manage Order at the bottom of the email.

You will be redirected to your MyOrder page, from where you can click on the button “More actions”. If an official resale option is available, it will show up here. You can then proceed to follow the steps to offer your ticket(s) for resale.