You cant really change the IP, but you can transfer all of your statistics to the new server.
Follow the steps bellow to move the data to your new server.
- Add "GameTrackerClaimServer" in your server name, in your server.ini file.
- Add the new server IP to GT.
- Go to your old server page. Click Manage.
- Scroll down to "Migrate Player Stats".
- Select your New server name from the menu.
- Click "Migrate stats FROM this server TO the selected server"
- Click Ok twice.
Now for the last step, under Delete server, click Delete, and then Ok.