Maybe I'm confused.
I thought a cm stood for centimeter, or 1/100th of a meter (approx. 3 feet).
That means 50 cm would be approx. 1 & 1/2 feet, and 40 cm would be about 1 foot 4 inches.
Or where did I go wrong?
high_man, you don't need to lst. Pot grows fine without it.
If you have height restrictions and the stem is thick, simply try bending the plant over. Use a sling like made out of cloth, tie that around the plant near the top, attach the sling to some good hemp twine (or string or rope, etc) and anchor it at the floor/tray. Do it mildly at first, then eventually train the plant in an upside-down U shape.
Pot is a very adaptable plant. For stealth purposes, I once grew some plants outdoors that I trained to grow horizontally. Every branch on the upper side of the stalk became like a little plant on it's own (or so it appeared from the air).