Ticket cancellation is only possible for privately held tickets and must take place by April 28, 2016. Cancellation fees are €5.95, plus handling fees. Overall cancellation fees for Standard Tickets are a total of €13,84 and €9,96 for a Reduced Ticket.
For more information, please contact Xing Event Team at https://de.amiando.com/help/ticketbuyer.
To save cancellation fees, it is also possible to sell a ticket you already purchased and have the name on the ticket changed accordingly. In that case, check the FAQ How do I transfer my ticket to another person?