As hosting providers, we can apply on the domain owner’s behalf, but we will need you to update your DNS A record with a new IP address before your certificate is generated.
You will find information on how to update your DNS A record on your provider’s site, for example:
https://www.namecheap.com/support/knowledgebase
https://uk.godaddy.com/help/ssl-certificates-1000006?isc=goemeu20
The new IP address will be 109.71.161.136
www.domainname.com DNS A record (www) to 109.71.161.136
domainname.com DNS A record (@) to 109.71.161.136
As usual, there is no need to modify the nameservers.