Item Upgrade in World of Warcraft
Item Upgrader Kit upgrade item is a system that allows players to upgrade their armor, weapons and trinkets over what they could acquire from Mists of Pandaria or Warlords of Draenor. It requires crests and currency and can be done at any NPC who upgrades items.
Items with high requirements generally get more value after upgrading (eth titans, for instance) While items with low requirements usually have less value since they can be rolled perfectly regardless of whether they upgrade.
Reroll tokens
Reroll tokens can be used for upgrading an item. They can be obtained from monsters and event rewards. They are available in three distinct subtypes; enhanced, rare and legendary. If a player owns an reroll token, they can right click a Satanic or Angelic item and select the option to reroll the value of the item. This process will consume the token used to reroll. Reroll tokens can be traded with other players.
Upgrades can boost the stats and power of an item upgrader kit.