To change your domain's IP address, just click on Actions > IP Address > Modify when you are in your domain group.
Then you will see a small popup window that gives you a list of available IP addresses that you have in your network.
Once you have changed your domain's IP address, our system will automatically reset your public DNS zone that's hosted with us. If you are using DNS services, registrar nameservers please update your domain's A record there as well.
Please also keep in mind that changing the IP address of your domain will reset your domain's SSL certificate as well. If you are using Let's Encrypt then our system will automatically install it for you.