As this has to be done on the OS level I reckon you can do a quick search online depending on what OS you're using.
In regards to 3CX, If you will be changing the SBCs local IP, remember that you will also have to update all IP Phone configuration in the 3CX Management Console with the new IP.
Go to "Users/Extensions >> Edit >> Phone Provisioning >> Select IP Phone from the drop-down >> in IP Phone section":
Apply the settings and then you will have to reboot the phones to have them reprovision with the new IP. I'd recommend doing this after you've actually got the SBC setup with the new IP otherwise the IP Phones will unregister until you do so.