Change IP?

Not possible. IP is ISP Based. I think this is against the ToS too.

If your on DSL, hardboot your modem, turn it off for 5 minutes, and then turn it back on.

If that does not help (which it will 90% of the time change your IP), use a proxy server, or proxy software.

Unplug your modem and plug it back in.

Couldn't you do this in cmd?

ipconfig/ release
ipconfig/ renew

Or would it not work for the game?

call your ISP and ask for a new IP

No, I have been banned a billion times, all you have to do it ipconfig /release as a couple people said.

Talking about IP evasion is against the ToS.

If you want to get back in, just have a word with the admin that banned you. I am sure there is a forum somewhere for that game server, and you can talk to him there.

Changing your IP to avoid a ban is against the TOS. If you were banned then you need to take it up with an admin on that server to get it sorted out.

Some ISPs assign IPs based on the modem serial number so even if you reset the modem it may not pull a new IP. Although they usually rotate IPs to keep people from hosting websites off of them that would require a static IP so they can charge more for it.

ipconfig /release and /renew won't work unless he's directly behind the modem. If he's behind a router then it only changes his internal IP, which the game server doesn't see.