There should be a way to delete the vertical curve without deleting the PVI, but we have not found it.

Sometimes, when designing the vertical, the AMax fallf low enough that the curve in no longer warented, but the PVI is still needed.

So we write down the station & elevation of the PVI, delete it, then put the PVI back in at the same place it was to begin with.

You should be able to just remove the curve.