Disambiguate Cloudflare Registrar role in update-nameservers.mdx

Author: RebeccaTamachiro

src/content/docs/dns/nameservers/update-nameservers.mdx

@@ -11,9 +11,11 @@ To use Cloudflare DNS as an authoritative DNS provider - be it in a [primary (fu
 
 ## Specific processes
 
-Although Cloudflare will [provide you the nameservers](/dns/nameservers/#authoritative-nameservers-offering) or allow you to create your own [custom nameservers](/dns/nameservers/custom-nameservers/), the final step to make Cloudflare an authoritative DNS provider for your domain may have to be done outside of Cloudflare.
+Although Cloudflare will [provide you the nameservers](/dns/nameservers/#authoritative-nameservers-offering) or allow you to create your own [custom nameservers](/dns/nameservers/custom-nameservers/), the final step to make Cloudflare an authoritative DNS provider for your domain may have to be done outside of Cloudflare. If you are not using [Cloudflare Registrar](/registrar/), consider which of the following sections correspond to your use case.
 
-Unless you are using [Cloudflare Registrar](/registrar/), consider which of the following sections correspond to your use case.
+:::note[Custom or advanced nameservers]
+If you are using Cloudflare Registrar with [custom nameservers](/dns/nameservers/custom-nameservers/) or [advanced nameservers](/dns/foundation-dns/setup/), note that you must [reach out to support](/support/contacting-cloudflare-support/) to have the nameservers updated accordingly.
+:::
 
 ### Your domain uses a different registrar