Master Wand( Complete Arcane, p. 192)
You can activate a wand without using a charge.
When you activate a wand, you can expend a spell slot instead of using a charge. The spell slot must be one you have not used for the day, though you can lose a prepared spell to emulate a wand charge (but you cannot lose prepared spells from a specialty school). The spell slot expended must be equal to or higher in level than the spell stored in the wand (including any level-increasing metamagic enhancements).