Thanks for writing in.
Little confuse of what you want to achieve. Do you want us to release the license so that you could give it to others or to your client? or do you want it to be revoked so that you could use them again to others sites?
To use them to other sites, just re assign again new domain in your license page.
For more details about product validation.
If you want to release a license, just reply with the API keys that you want to be released then you can give it to others.
Don't forget to add it in a secure note.
Let us know how it goes.