You can't. But you can empty it and create a new one. This is not advised unless you have a valid reason for changing the account.

1. Transfer any assets to your iLok.
2. Click "Remove" for each iLok. No iLok data should be displayed now.
3. In "Account Info", change your email address to some random characters.
4. Send an email to support-ilok@iLok.com informing us that your have emptied the account.
5. Create a new account, with a new name and register your iLoks.

In the future, for security purposes, PACE may restrict how many times an iLok can be removed from a registered account.