Google's John Mueller said that when you change your sites IP address, maybe because you are moving to a new server, it would be mostly a "non-issue" for ranking and SEO purposes. But it can have a temporary impact on your crawl rate as Google learns how much it can crawl the new server.
The question was asked on Reddit that said "Will we lose our Google rankings if we move our domain to a new IP?"
John Mueller said "It's fine. No worries." He said "at most you might see a temporary change in crawling rate (as Google's systems figure out how quickly the new server can be crawled), but otherwise it's a non-issue."
He did add this joke "Just don't move it to the 192.168.x.x range :-)"
Sometimes, but rarely, does your IP address change on your existing server. If that happens, I suspect Google thinks it is a new server and is a bit more careful crawling until it figures out how much stress it can put on the server.
Forum discussion at Reddit.
Update: Same messaging in 2021:
Changing IP addresses doesn't change much for search, at most er might need to figure out how fast to crawl the site again.
— 🧀 John 🧀 (@JohnMu) October 9, 2021