Maybe it can be done with coins or oort stones indeed, see my feature suggestion down below.
There was a topic about skill resets before: Skill removal points
Feature suggestion: skill reset
You can go to The Sanctum and talk to the NPC over there, then choose the option to reset your skill point. The NPC displays the costs for doing so and asks for confirmation. The cost could be in coins or oort stones, being more expensive each time you do the reset. Might even incorporate the level of the player in the calculation. This should prevent abuse as well (could even have a cooldown of a week).