Retrieve child objects by association - Self association

I have a entity with self-association that have an object of the same entity as its parent or children. I do not want to commit changes on this entity. I would like to retrieve a list of children objects associating from parent entity. Using association I am able to retrieve single parent object not a list of children's. Whereas using retrieval from the database I am able to retrieve a list of children's.

Could you please suggest me a way to retrieve a list of child objects using association not from the database.