Create an entity with the provided details, then associated it with a parent organisation.
The referenced parent entity must be of type ORGANISATION and an ownership query must have been previously completed.
At least the entity name (family name for individuals, registered name for organisations) must be provided in entity.
At least one of role or percentage held must be in the request. If either is null or omitted, then any existing details will
be retained. If either detail is given, the it will be replaced, not merged.