That is one of the good, old easy ones 😉........just cut off stem just over a leaf. Preferably not toohigh above the substrate, since new shoots will develop nicely from the cut stem.
Then remove one or two lowest leaves from the stem you cut off, and re-plant this in the substrate/gravel, covering the stem-part with no leaves. It will make new roots within a wek or so, and grow on.
The trick is to maybe make the "offcut" not too tall when replanted. That is done, by just cutting it in the length (from top) that you want, remove one or two leaves and re-plant this. It gives this new plant a little longer way to grow, before reaching surface again.
- Hyg. diff. is a healthy and fast grower......so you'll be doing this again and again.......and getting a lot of new plants to maybe give friends 🙂 🙂 🙂 🙂 🙂
Mick.