JK Rowling is well-known for her meticulous plans, with one example being the hand-drawn grid that she made to map the activities of her principal characters for the 750+ pages of The Order Of The Phoenix.
As most readers will have no doubt heard, she has previously explained that the story of Harry Potter appeared to her on a train almost entirely fully formed. Additionally, Rowling spent around five years planning and preparing before even the first book was ready for publication.
Despite this, as can be expected, some elements in her intricate plans did not appear as she had originally laid out. While she has given only a relatively small number of interviews, those that she has taken part in have been very revealing and honest. Her thoughts on Pottermore are similarly enlightening.
Some characters died who might have lived, while others who were due to make it to the end found their fortunes change for the worst. One character who would most likely have died is Hagrid, but he survived everything thanks to one of her plans which she would not waver on: as he carried baby Harry to safety in his arms, so he must be alive to carry him from the Forbidden Forest in the later moments of the final book.
Most of JK Rowling's intentions remained iron-clad, with only tiny details, if any, being adjusted. A number, however, turned out quite differently.