If you have a custom domain name connected to your site and would like to remove it, the first step is to remove the custom domain from your Portfolio site by
- Clicking into Settings in the left-hand panel
- Clicking into Domain Name
- Click Remove custom domain
To connect your custom domain to another Portfolio site, you will then need to re-configure the DNS records. More info here: Manually Configuring a Custom Domain
To direct your custom domain away from Adobe Portfolio, just edit your DNS settings with your domain name provider. You'll want to restore the A records to the default settings and make sure there is no trace of Adobe Portfolio IP addresses.