Extraordinary Spell Aim( Complete Adventurer, p. 109)
You can shape a spell's area to exclude one creature from its effects.
Spellcraft 15 ranks,
Whenever you cast a spell with an area, you can attempt to shape the spell's area so that one creature within the area is unaffected by the spell. To accomplish this, you must succeed on a Spellcraft check (DC 25 + spell level). Casting a spell affected by the Extraordinary Spell Aim feat requires a full-round action unless the spell's normal casting time is longer, in which case the casting time is unchanged.