She pointed her wand at the pad

She pointed her wand at the padlocked and heavily graffitied fire door beside them, which burst open with a crash. The dark corridor behind it led, as they knew from their careful scouting trips, into an empty theater. Hermione pulled the door back toward her, to make it look as thought it was still closed.
“And now,“ she said, turning, back to face the other two in the alleyway, ”we put on the Cloak again – “
“ – and we wait,” Ron finished, throwing it over Hermione’s head like a blanket over a birdcage and rolling his eyes at Harry.
Little more than a minute later, there was a tiny pop and a little Ministry witch with flyaway gray hair Apparated feet from them, blinking a little in the sudden brightness: the sun had just come out from behind a cloud. She barely had time to enjoy the unexpected warmth, however, before Hermione’s silent Stunning Spell hit her in the chest and she toppled over.
“Nicely done, Hermione,“ said Ron, emerging behind a bin beside the theater door as Harry took off the Invisibility Cloak. Together they carried the little witch into the dark passageway that led backstage. Hermione plucked a few hairs from the witch’s head and added them to a flask of muddy Polyjuice Potion she had taken from the beaded bag. Ron was rummaging through the little witch’s handbag.
“She’s Mafalda Hopkirk,“ he said, reading a small card that identified their victim as an assistant in the Improper Use of Magic Office. ”You’d better take this, Hermione, and here are the tokens.“
He passed her several small golden coins, all embossed with the letters M.O.M. which he had taken from the witch’s purse.
Hermione drank the Polyjuice Potion, which was now a pleasant heliotrope color, and within seconds stood before them, the double of Mafalda Hopkirk. As she removed Mafalda’s spectacles and put them on, Harry checked his watch.
“We’re running late, Mr. Magical Maintenance will be here any second.”
They hurried to close the door on the real Mafalda; Harry and Ron threw the Invisibility Cloak over themselves but Hermione remained in view, waiting. Seconds later there was another pop, and a small, ferrety looking wizard appeared before them.
“Oh, hello, Mafalda.”
“Hello!“ said Hermione in a quavery voice, “How are you today?”
“Not so good, actually,” replied the little wizard, who looked thoroughly downcast.
As Hermione and the wizard headed for the main road, Harry and Ron crept along behind them.
“I’m sorry to hear you’re under the weather,” said Hermione, talking firmly over the little wizard and he tried to expound upon his problems; it was essential to stop him from reaching the street. “Here, have a sweet.”
“Eh? Oh, no thanks – ”
“I insist!“ said Hermione aggressively, shaking the bag of pastilles in his face. Looking rather alarmed, the little wizard took one.
The effect was instantaneous. The moment the pastille touched his tongue, the little wizard started vomiting so hard that he did not even notice as Hermione yanked a handful of hairs from the top of his head.
“Oh dear!” she said, as he splattered the alley with sick. “Perhaps you’d better take the day off!”
“No – no!” He choked and retched, trying to continue on his way despite being unable to walk straight. “I must – today – must go – ”
“But that’s just silly!” said Hermione, alarmed. “You can’t go to work in this state – I think you ought to go to St. Mungo’s and get them to sort you out.”
The wizard had collapsed, heaving, onto all fours, still trying to crawl toward the main street.
“You simply can’t go to work like this!” cried Hermione.
At last he seemed to accept the truth of her words. Using a reposed Hermione to claw his way back into a standing position, he turned on the spot and vanished, leaving nothing behind but the bag Ron had snatched from his hand as he went and some flying chunks of vomit.
“Urgh,” said Hermione, holding up the skirt of her robe to avoid the puddles of sick. “It would have made much less mess to Stun him too.”
“Yeah,” said Ron, emerging from under the cloak holding the wizard’s bag, “but I still think a whole pile of unconscious bodies would have drawn more attention.
Keen on his job, though, isn’t he? Chuck us the hair and the potion, then.”
Within two minutes, Ron stood before them, as small and ferrety as the sick wizard, and wearing the navy blue robes that had been folded in his bag.
“Weird he wasn’t wearing them today, wasn’t it, seeing how much he wanted to go? Anyway, I’m Reg Cattermole, according to the label in the back.”
“Now wait here,” Hermione told Harry, who was still under the Invisibility Cloak, “and we’ll be back with some hairs for you.”
He had to wait ten minutes, but it seemed much longer to Harry, skulking alone in the sick-splattered alleyway beside the door concealing the Stunned Mafalda. Finally Ron and Hermione reappeared.
“We don’t know who he is,“ Hermione said, passing Harry several curly black hairs, ”but he’s gone home with a dreadful nosebleed! Here, he’s pretty tall, you’ll need bigger robes …“
She pulled out a set of the old robes Kreacher had laundered for them, and Harry retired to take the potion and change.