Change URL from WHM

Hello all,

I am pretty new to WP and own my hosting service through WHM.

A costumer is changing domain name from

http://curiosidadesgastronomicas.com/

to

http://curiogastro.com/

So first I changed the site URL from WordPress. Then I changed the URL from Web Hosting Manager. This kept all the WP files in place, but the site went to a blank page.

So what can I do to restore the site? Do I have to open a new hosting service for the new domain name?

Or is there a way I can keep the WP install but redirect everything from MySQL?

I know this page https://codex.wordpress.org/Changing_The_Site_URL

But I don’t want to screw everything up. That’s why I’m asking first.

Thanks!