Your can delete your domain name anytime. The serving Registrar will initiate the process at your request. You will be notified by an auto-generated email, to verify your intent. After receiving your confirmation, your domain name will be set a pending quarantine status. Your domain will remain in this status for 30 days, after which it will be purged and dropped from the registry database.
If you have not received auto-generated email, you can use the template form on this page to confirm your intent.
N.B. Think carefully about deleting a domain name. If you change your mind after sending a confirmation, a domain name scheduled for deletion can be recovered only by requesting a domain renewal. Domain renewal, however is a chargeable service.