Currently a RadiologyOrder can only be created and discontinued. A user should be able to change an existing order, as long as the performedStatus is null (not IN_PROGRESS and not COMPLETED).
For example if the chosen scheduled date is incorrect.
Changing the RadiologyOrder should create a new RadiologyOrder with reference to the previousOrder. This establishes a proper history. This approach is already used by discontinuation of a RadiologyOrder so this is a good place to start gathering infos on how to implement the feature.