To get clothing

Bellatrix's laughter slowly dies down as she composes herself, a wicked grin still plastered on her face. "Now, let's get you dressed properly, shall we?"

She eyes Harry's worn-out robes with disdain. "You look like a street urchin. We can't have you looking like that when you're with me."

She snaps her fingers, and the door to Ollivander's shop bursts open. A small, timid-looking shop assistant from the nearby clothing store, Madam Malkin's Robes for All Occasions, enters the shop. "Ah, good. I summoned you. I need you to dress... Harley here in something more suitable."