A "renewal" is actually just another new one.
There is no way to make even the tiniest of modification to a cert.
Any change requires a new cert.
"renewal" is just for humans to "understand" the process.
When your credit card expires they issue you a new one.
You can think of it as renewing the previous card, but the truth is they are two completely independent cards [sometimes even the entire number can change].
In that same sense, certs change just as completely.