Netlify Custom subdomain - replace a wordpress website

Hi guys, I built a website in reactjs (and gatsby) and now it’s hosted on netfly. The firm I work for created a subdomain for me mysite.firm.com. Both firm.com and mysite.firm.com host a wordpress site. Can I replace mysite.firm.com (wordpress) with the react site I built simply using the “set custom domain” tool and typing mysite.firm.com on Netlify?
I apologize if any term is not technically correct but I am new to this kind of thing

Hi @AC1design! Welcome to our Community.

There is actually a two-step process to adding a subdomain custom domain.

First, log on to your Netlify account and add the subdomain to your Netlify site via our UI.

Then, create a DNS record at your DNS provider following these instructions: https://docs.netlify.com/domains-https/custom-domains/configure-external-dns/#configure-a-subdomain

Let us know how it goes!

Hi thanks for your reply! the problem is that the don’t own /firm.com/ so I can’t log in to dns provider. They just gave me a subdomain that now hosts a worpress website. Should I ask the owner to do it or is there an alternative way?

Yup, it will require them to change DNS. That’s in essence the “phone book” of the internet, and until the listing is updated - the old number will be used by your web browser (and everyone else’s). You can fake out your web browser if you want, but it won’t help anyone else…

Those who manage the DNS can of course choose to JUST change the mysite.firm.com name for testing purposes, of course!