He knew he was too early to meet Hermione, but he thought it likely there would be someone in here with whom he could spend the intervening time.
’Well, anyway,’ said Hagrid quickly, intervening before Ron could answer back, ’Dumbledore’d bewitched this branch to burn fer evermore, which isn’ somethin’ any wizard could do, an’ so I lies it down in the snow by Karkus’s feet and says, "A gift to the Gurg of the giants from Albus Dumbledore, who sends his respectful greetings.’ "
Harry remembered Lupin saying back in Grimmauld Place that Dumbledore had made him prefect in the hope that he would be able to exercise some control over James and Sirius… but in the Pensieve, he had sat there and let it all happen… Harry kept reminding himself that Lily had intervened; his mother had been decent.
…for the Snitch, keeping one eye on Malfoy in case he showed signs of having spotted it, but Malfoy, like him, was continuing to soar around the stadium, searching fruitlessly… ’— Pucey throws to Warrington, Warrington to Montague, Montague back to Pucey —Johnson intervenes, Johnson takes the Quaffle, Johnson to Bell, this looks good — I mean bad — Bells hit by a Bludger from Goyle of Slytherin and it’s Pucey in possession ’WEASLEY WAS BORN IN A BIN HE ALWAYS LETS THE QUAFFLE IN —>.
There are no more uses of "intervene" in the book.