From HEXONET Wiki
The DeleteDomain command can be used to delete a domain. The domain will be deleted as soon as the command has been submitted to the system.
IMPORTANT: Please have a look at the Domain API-Manual for a current list of allowed parameters.
(required) command = DeleteDomain domain = (DOMAIN) (optional) x-at-scheduledate = expiration | now
(required) code = (CODE) description = (DESCRIPTION)