Skill Reset Capsule
With Fantasy Life Club or Advanced Play services, you will receive Skill Reset Capsule randomly. When used, it will reset a skill of your choice by one level (Rank F is the lowest) and return the Ability Points used to learn that skill. NOTE: This item cannot be traded with other players.
Allows the user to lower a skill by one level (though not below Rank F) and reclaim the associated AP. Be aware that any gains associated with the skill rank are also removed (e.g. lowering Fishing from Rank D to Rank E will also take away the gained +1 Dex). Though the quote states they are obtained randomly, skill reset capsules are also one of the items of the day on Saturdays and can be received by choice each week on that day. If you use a skill reset capsule to reset a skill, it will be reset at maximum training exp, but you will not gain full training exp from ranking it again.
Skill Reset Capsules cannot be traded, sold in player shops, put into pets' inventories, or withdrawn from your bank account by your other characters using Extra Storage or Fantasy Life Club.
Duncan has a similar ability to the Skill Reset Capsule. For characters under cumulative level 1000, Duncan is capable of freely resetting all of the character's skills back to F, returning all the AP used.