It shows as offline because it is no longer at the address it was before because you changed it, and it was offline before that because it was on a different IP scheme than it is now and was not part of your new subnet (Basically, it was on a 192.168.0.x address and the new one is 192.168.1.x, obviously this is not the exact schemes in play, but it is likely to be what happened)
So if you gave it an IP address that fits on your LAN, it will be viewable from your PC in a web browser (put the IP where you would put a web address) And if that is the case, you can simply modify the port in the driver.
Since you neglected to mention an OS on the PC's, I'm playing safe and betting Windows 7, but the steps will be near identical for all Windows versions.
Go to Start > Control Panel > Devices and printers and then right click on the printer and choose Printer Properties
Go to the Ports(1) tab and then select Configure Port (2)
Note you cannot change the name, but you can change the IP address (3). So do so and then click OK > Apply > OK.
It should work fine then.