And near the end of Book 3 of The Chronicles The Voyage of the Dawn Treader as Edmund and Lucy find that they have to go back to their world and will not be coming into Narnia anymore

Lucy sobs, “It isn’t Narnia, you know, it’s you. We shan’t meet you there. And how can we live, never meeting you?” “But you shall meet me, dear one,” said Aslan “Are – are you there too, Sir? Said Edmund. “I am,” said Aslan, “But there I have another name. You must learn to know me by that name. This was the veery reason you were brought into Narnia, that by knowing me here for a little, you may know me better there.”(LWW)