Jaiminīya Upaniṣad Brāhmaṇa 3.28.4

3.28.4

sa yadi kāmayeta punar ihājāyeyeti yasmin kule 'bhidhyāyed yadi brāhmaṇakule yadi rājakule tasminn ājāyate
sa etam eva lokam punaḥ prajānann abhyārohann eti /

If he should desire: “May I be born here again,” into whatever family he sets his mind—whether into a family of Brahmins or into a family of kings—into that he is born.
Knowing again, he goes climbing up into this very world.