How to replace a Volume Profile during runtime?

You can reference a profile and a volume as below

 public Volume volume;
 public VolumeProfile profile;

Create a PP profile and save in your assets as a prefab, assign it to profile, assign your gameobject with a PP Volume to volume

You can switch the profile whenever you want with

 volume.profile = profile;

You will also need to reference

 using UnityEngine.Rendering;