Hogwarts occurring is a passage to the Hog's Head bar that formed before the Battle of Hogwarts. Due to the nature of the Room of Requirement, it is possible that several passages to different locations could be accessed from the Room. The three passages out of Hogwarts that Filch does "not" know about are: A further link between two vanishing cabinets, one in the school and the other in Borgin and Burkes in Knockturn Alley presumably worked until "Chamber of Secrets" when Peeves (persuaded by Nearly Headless Nick) smashed the Hogwarts cabinet. The passage was reopened in "Half-Blood Prince" when Draco
Hogwarts staff in "Half-Blood Prince", she becomes the acting Headmistress of Hogwarts. However, in the series finale, she does not become headmistress at the start of term as expected; Snape is appointed by the new Minister for Magic Thicknesse, who is actually under the Imperius Curse and acting for Voldemort. Death eater Alecto Carrow replaces McGonagall as deputy headmistress. Despite the many changes, she is retained as head of Gryffindor House. Before the Battle of Hogwarts, she goes to the Ravenclaw tower and finds Alecto stunned by Luna and Amycus Carrow searching for Harry. She's surprised when Amycus tells her Voldemort warned