If you're comfortable in SQL, you can edit the dbo.VPX_HOST table in vCenter to change the IP_ADDRESS field to whatever you want.
Otherwise, power up the host with the new IP. Then from vCenter, attempt to reconnect (which will fail), at which point you'll be prompted to enter the name, root user, and password to connect to the host. You can then use the new IP address.
Also, even without DNS, you may want to edit the hosts file on the vCenter server and use hostnames for the servers moving forward to avoid this complication. Much simpler to edit a hosts file.
Edit: Just for giggles, I changed the IP on a lab host while it was online and connected to vCenter, in which it disconnected and then reconnected with the proper IP. So, I suppose that works too :smileyhappy: