Move domain from one cloudflare account to another

How can I move a domain that is registered under one account to another cloudflare account?

See https://support.cloudflare.com/hc/en-us/articles/204615358-Moving-domains-between-Cloudflare-accounts

You most likely can’t, as the registrar really isn’t set up for this. At best, you can open a ticket and ask, but you’re most likely going to get some pushback.