She has said that she is done with the wizarding world, and she will not allow anyone else to write about Harry. I feel like she left open to come back to Harry one day, but after all these years of writing about him she feels it is complete. I do not know if she will grant someone else the right to write about him, but as of now she will not allow anyone else to write about Harry, while she is living or after she is dead. Not sure if it will be as good if someone else wrote about Harry, she knows him better then anyone as she created him.