Show different site for already Transferred Domain

I have a custom domain on namecheap connected successfully (domain transferred?) to a site I have running here on Netlify. Now I want to use the same domain but connect it to a different site I have running here on Netlify. How would I transfer that over? (Also please forgive me if my descriptions or terminology is incorrect)Thanks!

Normally, by deleting the custom domain configuration from the first site (found under Site Name > Settings > Domain management > Custom domains) and then adding it to the same place for the new site.

Note, unless you are using Managed DNS, this also requires updating the DNS records with your DNS service to point to the new Netlify subdomain.