Please follow the below steps to remove an IPv6 range.

1. WHM: Home »IP Functions »IPV6 Ranges
   
   
2. Find the IPv6 Range you wish to remove and click the ‘Delete Range’ button.
   
3. If the IPv6 Range ‘Delete Range’ button is greyed out, then navigate to the following location:
   WHM: Home »IP Functions » Assign IPv6 Address
4. And disable the IPv6 address for any accounts using the IPv6 range.