Harry went to the restricted area of the library to look for clues about Nick Flamel. It's not that his menstrual family suddenly changed houses. Because Harry's letter was an admission notice from Hogwarts at that time, his uncle didn't give it to Harry. He didn't want Harry to have anything to do with magic, so he didn't read the letter to Harry. But there are more and more owls, and the house is almost full. His uncle wanted to move to another place so that the letter could not be sent, so he moved, and then Hagrid personally brought the admission notice to Harry and changed the house.