To buy a stat reset, open the "D" menu in the game and go to the second page. This feature only works in town.
Select the free stat reset subscription period that suits you and click the "Buy" button.
Warning: the game does not ask for confirmation after you click Buy. Be careful!
After the purchase, you will be taken to the main menu of the game client. When you log back into the game, resetting your character's stats will be free until the end of the subscription period.