To update the details of any dog on your account use the "Dogs" option on the "My Account" Menu or click the link below :
If you wish to remove the dog completely from Champdogs use the delete link next to the relevant dog.
Alternatively you can add the Dog to the Rainbow Bridge section of your account by using the update link and adding its date of death. The "date of death" field can be found on the "List Options" update screen.