I am not sure how to do that, but let's say you have a planet and you want a satelite to revolve around it. A quick and dirty way would be this:
1) Create a Position3D
node and place it at the center of the planet.
2) Have the Position3D
node update its rotation any way you like.
3) Make the Position3D
node a parent to the satelite.
4) Place the satelite as far or close as necessary to the planet.
5) Voila! Your satelite revolves around the Position3D
node, which in turn rotates the way you like. That way you also avoid making the planet a direct parent to the satelite.
For a more advanced way, read up on this:
https://godotengine.org/qa/34248/rotate-around-a-fixed-point-in-3d-space
I am not sure, but I think this atan
method looks promising. You could also google "Godot orbit", since what you want is technically orbital movement. I hope this helps.