Stairs of Mail

During your Main Phase: You can activate this effect; discard 1 "Tindangle" card, and if you do, apply 1 of these effects.
● Change 1 face-down Defense Position monster you control to face-up Attack Position.
● Change 1 face-up Attack Position monster you control to face-down Defense Position.
This turn, you cannot discard another card with the same name for the effect of "Stairs of Mail" (even if this card leaves the field).