There is no way as a user to remove them, what u will have to do is go to live chat and confirm that u are the owner of the account and let them remove it for you.
I have actually gone through support and the GM said that they are not allowed to remove any licenses (banned or not) that are on the battlenet. They can only remove "Starter" accounts.
u can move any account for other bnet in your name, but u cant move the banned ones, and i multibox with 5 account and the banned accounts in the old battle net wont allow me to have new 5 on that 10 years old bnet with all mounts and pets and achievs