Set it’s global_position-property. Attach a script to your KinematicBody2D:
extends KinematicBody2D
func teleport(to):
global_position.x = to
Then call this function like this teleport(Vector2(1500,-500)) from somewhere else in the script. If you want to trigger the teleportation from a script attached to a different node, you will need to first get the correct node with get_node().
Booth works, but this is a little bit better, because I have a function, which can be called from everywhere in the script.