Can the Room of Requirement be Two Things at Once?

Question

Throughout the Harry Potter story, we've seen the Room of Requirement be a number of different things. It can be a place for Dumbledore's Army to practice, or an extremely huge closet filled with uncountable items (including a horcrux), and more.

But can it be two different things at the same time? For instance, could Harry and Dumbledore's Army be using it for practice and, while they're practicing, could Snape use it as the huge closet so he could slip in and hide something? And if it's being two or more things at once, to different people, would they have any way of knowing that while they're in it, someone else is in another "version" of the Room of Requirement?

Answer 1

Nope. In the sixth book, prof Trelawney tries entering while Malfoy is already inside.

The Room of Requirement,' repeated Harry. 'Were you try-ing to get in there?'

'I - well - I didn't know students knew about -'

'Not all of them do,' said Harry. 'But what happened? You screamed ... it sounded as though you were hurt...'

'I - well,' said Professor Trelawney, drawing her shawls around her defensively and staring down at him with her vastly magnified eyes. 'I wished to - ah - deposit certain – um - personal items in the Room ...' And she muttered something about 'nasty accusations'.

'Right,' said Harry, glancing down at the sherry bottles. 'But you couldn't get in and hide them?'

He found this very odd; the Room had opened for him, after all, when he had wanted to hide the Half-Blood Prince's book.

'Oh, I got in all right,' said Professor Trelawney, glaring at the wall. 'But there was somebody already in there.'

'Somebody in -? Who?' demanded Harry. 'Who was in there?'

' I have no idea,' said Professor Trelawney, looking slightly taken aback at the urgency in Harry's voice. 'I walked into the Room and I heard a voice, which has never happened before in all my years of hiding - of using the Room, I mean.'

Later on, she says

Everything went pitch black and the next thing I knew, I was being hurled headfirst out of the Room!'

So basically, she tried entering the room when Malfoy was already in it, and thus entered the same room that Malfoy was in.

Another scenario is in the Deathly hallows, where Harry needs to empty the room to search for the diadem:

He knew that the room would not be able to transform while there were still users inside it. .... “Ginny,” said Harry, “I’m sorry, but we need you to leave too. Just for a bit. Then you can come back in.” Ginny looked simply delighted to leave her sanctuary. “And then you can come back in!” he shouted after her as she ran up the steps after Tonks. “You’ve got to come back in!”

Answer 2

No. When Harry and company needed to get into the Room of Hidden Things to find the diadem, they had to get the remaining occupants out so they could change it.

Answer 3

I thought the answer was no as well. However, if this is true, then the next scene after Harry asks Ginny to leave, does not make sense. Harry enters the Room of Hidden and races down to the item he is looking for and a guest who is there to meet him? Malfoy and his hoodlums. How were Malfoy, Goyle, and Crabbe in the room when Harry and company were in the other room? If you argue that Malfoy, Goyle, and Crabbe followed after Harry and company into the Room of Hidden, which would follow the one-room logic, but then how do they get too ahead of Harry and company? There is a logic flaw here. So in all, yes.

Answer 4

The Room of Requirement cannot be two things at once. This can be easily concluded from two extracts from the Harry Potter series:

1. 'Malfoy got into our Headquarters there last year, so I'll be able to get in and spy on him, no problem,' said Harry.

   'But I don't think you will, Harry,' said Hermione slowly. 'Malfoy already knew exactly how we were using the Room, didn't he, because that stupid Marietta had blabbed. He needed the Room to become the Headquarters of the DA, so it did. But you don't know what the Room becomes when Malfoy goes in there, so you don't know what to ask it to transform into.'

   _{Harry Potter and the Half-Blood Prince: The Unknowable Room}

   Thus, the room can take only that form which one thinks of, or rather requires. No one can enter the same room as the one already being used by someone unless one knows how the other is using it.

2. He [Harry] knew that the room would not be able to transform while there were still users inside it.

   _{Harry Potter and the Deathly Hallows: The Battle Of Hogwarts}

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After applying deductive logic, we reach the conclusion that one cannot use the Room of Requirement if there is already a user inside and his/her use of the room is different from how one intends to use it. This argument clears all those doubts which the accepted answer can not.