Ray tracing with dynamically added/deleted objects

Most of objects in my scene are added at the beginning of the application. I used RayTracingAccelerationStructure.AddInstance to add all corresponding renderers in my acceleration structure and called RayTracingAccelerationStructure.Build to build the structure.

In the Update function, I called RayTracingAccelerationStructure.UpdateInstanceTransform for all moving objects and then called RayTracingAccelerationStructure.Update to update the structure.

Some objects are dynamically added to the scene and some are deleted. How should I deal with such objects?
* When an object is added to the scene, I can call RayTracingAccelerationStructure.AddInstance to add its renderers. Do I have to call RayTracingAccelerationStructure.Build again? Or is RayTracingAccelerationStructure.Update enough?
* When an object is removed from the scene, how can I delete it from the RayTracingAccelerationStructure? (There is no method like RayTracingAccelerationStructure.RemoveInstance).