In order to enchant a skill, you may have to find a specific NPC. There are currently 22 NPCs in the game that allow Skill Enchantment; among these, you must find the one who fits both your race and your occupation or the enchantment cannot progress. Listed below are the NPCs you should seek:
Sedrick's Training Hall in the Town of Aden:
Master Aiken, Master Sinden
Einhasad Temple in the Town of Oren:
Priest Vadin, Priest Egnos
Oren's Ivory Tower:
Magister Marina, Magister Joan, Magister Ladd
Hardin's Academy:
Master Galadrid, Magister Anastia, Dark Knight Mordred, Lich King Icarus
Fighters Guild in Hunters Village:
Master Aren Athebalt, Master Stedmiel
Rune Township Fighters Guild:
Prefect Tazki
Rune Township Sage's Library:
Seer Mekara
Rune Township Blacksmith:
Blacksmith Vincenz
Rune Township Warehouse:
Warehouse Keeper Hugin, Warehouse Keeper Durin, Warehouse Keeper Lunin, Warehouse Freightman Daisy
Kamael Village:
Master Nerga, Master Xonia