*The character must be able to equip both items.
*Only common (green), rare (blue) or epic (purple) items may be transmogrified (exceptions: a select few of these items will be prevented from being used to transmogrify if they are inappropriate). Blizzard apparently thinks of heirloom as rare?
*Heirlooms and Account Bound items can be transmogrified.
*Heirlooms and Account Bound items can be used to transmogrify.
*At this point only appearance can be changed, stats can not be moved.
I*tems must share the same armor type (examples: plate for plate, cloth for cloth).
*Weapons must be the same weapon type (exceptions: Guns, Crossbows, or Bows).
*Guns, Crossbows, and Bows can be used to transmogrify Guns, Crossbows, or Bows.
*Main hand weapons can only be used to transmogrify Main hand weapons.
*Off-hand weapons can only be used to transmogrify Off-hand weapons.[citation needed]
* handed weapons can be used to transmogrify a Main hand or Off-hand weapon.
*Using an item for transmogrify makes it soulbound.
*Using an item for transmogrify makes it non-refundable.
*Using an item for transmogrify makes it non-tradable. Seems redundant with soulbound.
*Legendary items cannot be transmogrified.
*Legendary items cannot be used to transmogrify.
*Fishing Poles cannot be transmogrified.
*Fishing Poles cannot be used to transmogrify.
*Mailing an item strips its transmogrification.[3]
* Placing an item in Void Storage strips its transmogrification.
* Vendoring an item strips its transmogrification.
*The displayed enchant will be that of the currently equipped item.
*There may be individual items that are excluded from being transmogrified on the basis that they were originally added to the game as absurdities. (examples: a weapon that looks like a fish, or a chest piece that is invisible).