You can't define new buffs. You can only edit existing buffs. You have to take into account that the buff of the original ability will also be changed so it might not be a good idea to change the buff.
Originally posted by 35263526 There are no promises, but it seems an extremely likely possibility that Path 1.13 will include Buff Editing. So maybe you'll get lucky then.
Can you tell me where you got a hint to that great feature? Did Brett post something? Can you link me?