Accesing later in the game

While your creature evolves, its cells could still change as well, especially if they had new organs that needed new tissues. Perhaps, in the organism editor, there would be a button to press that would make the cell editor pop up, allowing you to edit cells, and then send tissues of those cells to the organism editor.
Also, once your species has unlocked genetic engineering, they would be able to access the editor as well. How would it be different?