Well if you in shared hosting or Managed VPS just
order a new IP (if you mean IP)
If you mean the domain name like
just order to a domain provider and inform your WordPress.
Is going to be SEO problem and needs redirects for already posts esist under to old domain
1. Change the Domain in WordPress. Log into your WordPress account, and from the dashboard, go to Settings > General. Change both the WordPress Address and Site Address to your new domain name, then save.