Today to change this site from https://cloudzhong.top to https://unki.net, we need to modify the certification.
here is the step to add a site to the old certification.
acme.sh --issue -d cloudzhong.top -d unki.net --nginx
this command add a -d parameter to a new domain name.
Then from certification’s alter name , we can saw that new site is added there.

and then modify wordpress URL to new url.

and then reload nginx to get the new certification.
systemctl reload nginx
and still there is many plugins also needed actions to change the url, this is not included in this blog.