What do you mean by assign to hosting account and register from cPanel? If you mean your forum account, I don't think we delete forum accounts.
The following is to delete your hosting account:
Fill this out and post here:
cPanel username:
( ) Inserting an X inside the parentheses signifies that I have made all necessary backups of my free hosting account and will not hold x10Hosting responsible for any data I am unable to recover after my free hosting account is deleted. The X also serves as my digital signature verifying that I have proper authorization to request account deletion of the account specified.
A staff/community helper would be able to help you afterwards.