If you want to delete your ENUM domain, please contact your provider. Make sure to tell your provider clearly that you want to completely give up and delete your ENUM domain. Most providers ask their customers to use special forms for a deletion request.
DENIC will only accept deletion requests submitted by the DENIC member who is, at the time of such request, in charge of the ENUM domain in question.
Please note: Once a deletion has been carried out by DENIC, the corresponding domain cannot be restored without the involvement of a provider. If you want to go on using an ENUM domain, you have to request a provider to register the deleted domain again with DENIC.