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Here she clearly states that she's never used Obliviate.
"You're the boss," said Ron, sounding profoundly relieved. "But I've never done a Memory Charm."
"Nor have I," said Hermione, "but I know the theory."
(Deathly Hallows, Chapter 9, A Place to Hide).
Yet in a previous chapter she seems to contadict that.
"I've also modified my parents' memories so that they're convinced they're really called Wendell and Monica Wilkins, and that their life's ambition is to move to Australia, which they have now done...Assuming I survive our hunt for the Horcruxes, I'll find Mum and Dad and lift the enchantment. If I don't - well, I think I've cast a good enough charm to keep them safe and happy."
(Deathly Hallows, Chapter 6, The Ghoul in Pyjamas).
If she had modified her parents' memories already then why did she claim to have never performed a Memory Charm?