If there's no "Add" on the page where you see the APN, it's not a function that Verizon left in the ROM. About the only way to "restore" it would be to flash a different ROM that would still work on Verizon. (Cyanogen 11 still has a few bugs on Verizon, like GPS. I don't know if adds an Add to the APNs.)
Question:
Since you're most likely using the phone on Verizon towers, why would you want to change the APN? The APN data depends on the towers the phone is using.