A developer set up my website many years ago, and holds the registered email for cloudflare. I need to release the name server configuration so that I can repoint my new website.
What feature, service or problem is this related to?
If the Cloudflare account is not yours, then you won’t get access to it.
You will need to change the nameservers set at your domain registrar to those for a new Cloudflare account of your own, or another DNS provider, to take control of your domain.