This may seem like a silly question, but is it possible to upgrade a magical item's quality? My level 12 druid just picked up craft woundrous items because no one in the area sells amulets of natural armor and she really needs more armor. What I'm curious about is, if she makes an amulet of natural armor +3, can she later upgrade it to an amulet of natural armor +4 without having to wipe out the enchantment and start over (thus spending the raw materials and exp cost all over again)? Can she pay the difference in raw materials and exp between the +3 and +4 amulets? Any thoughts on this?