What happens when updating the parent of an existing entity causes it to no longer have any parent?

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If updating the parent of an existing entity causes it to no longer have any parent, the entity becomes a root entity in the hierarchy. This essentially means that it moves up to the topmost level of the hierarchy and becomes independent of any parent entities. Any child entities that were associated with the previous parent will now become direct children of the root entity. This change in the hierarchy structure may have implications for the relationships and permissions associated with the entity, and may need to be handled accordingly.