Text (MM+errata): You may exile a blue card from your hand rather than pay ~this~'s mana cost. ; Change the target of target spell with a single target. [Oracle 2009/07/08]
You choose the spell to target on announcement, but you pick the new target for that spell on resolution. [bethmo 1999/11/30]
If there is no other legal target for the spell, Misdirection does not change the target. [D'Angelo 2000/07/24]
Misdirection does not check if the current target is legal. It just checks if the spell has a single target. [DeLaney 2001/02/15]
