Changing domains name server under cloudflare domain registry

I have domains under cloudflare registration. I don’t how to change their cloudflare name servers value.
HOW

Unfortunately, Cloudflare Registrar only lets you use Cloudflare name servers…so far.

I’m trying to update cloudflare name servers from
isaac.ns.cloudflare.com ,sue.ns.cloudflare.com

to
damian.ns.cloudflare.com, nena.ns.cloudflare.com