All domain name registrations are final. This is why it is very important to check your order before confirmation.
If you have a domain name reseller formula, you made a mistake by registering a domain name and you do not want to keep it, go to your reseller interface and make sure that you have the "Auto-Renew" option "is disabled for this domain. This will prevent the latter from being automatically renewed on its expiration date and will subsequently be deleted.