Sorry, the question is a bit strange. My plesk panel generates a preview link before the DNS is switched over, for previewing sites. I am also new to plesk, so not completely sure on this one. I gave up and just bought a domain for testing purpose, I can set everything up there and allow the client to preview and then transfer to the domain when ready. Hopefully, most of my clients will not have blogs pointed to their domain name and I can just build it there directly.