Running new site on Windows Server 2012 R2 IIS.
I have a domain which i have had for several years and is registered with search engines and is hosted with "Host 1", for this example i will call it
I have a second domain https://www.newexample.com which is brand new and is on Host 2.
Feel free to ask more questions if this doesnt make sense.
No it would never kill or affect the SEO for site one https://example.com. Redirect it to website two. Using js
<script>windows.location = "http://newsite.com/";</script>
Plus point is your new site ranking will also be increased by redirecting it to new domain.
SEO is they way the site is constructed to make its content understandable to web engines. The new site can have better or worse SEO score, depending on if best practices were followed while constructing it.
I am assuming you are talking about search engine ranking. What you need to do is set up a 301 ("moved permanently") redirection on the server you are using. All new requests for
www.example.com will be redirected to
www.newexample.com and at the same time you will be signalling to search engines that the content of the request was moved permanently to a new URL.
Given some time, all the ranking of your old site will be redirected to your new site.