If a person weighs 600 N on Earth, they would weigh less on a planet with a larger radius. The weight of an object is determined by the force of gravity acting on it, and the force of gravity is directly proportional to the mass of the object and inversely proportional to the square of the distance between the object and the center of the planet. As the radius of the planet increases, the distance between the object and the center of the planet increases, which would decrease the force of gravity acting on the object and therefore decrease the object's weight.
It's worth mentioning that the mass of the person would be the same, so their weight would change due to the gravitational force.