Yes you can, pretty easily. I just went back from cell phone to landline. You should get your original landline calling plan back, and any leftover cell phone airtime or minutes will be credited to your landline account after a couple billing cycles.
I was told only if the area code AND prefix are assigned to the physical area where the landline would be installed. In my case I was in the region for the area code but not the prefix, so Verizon could not port my TracFone to a landline.