How can I change our cpanel nameserver to be non-authorative for a domain?

When looking up ourdomain.com through dns.ourdomain.com (one of our old nameservers), it returns an authorative response as it should, all well. But, when I look up ourdomain.com through ns1.ourdomain.com (new nameserver with cpanel where the website is also set up) it also returns an authorative response, which it should not. How can I edit the site/dns record in cpanel to make ns1.ourdomain.com non-authorative?