Don't worry, they're not taking away or changing the original scent. CHANEL always takes the original scent (in this case the Eau de Parfum) and heightens certain scent notes in order to offer a slightly different version of the same scent. That way every woman can pick her own favorite version of the scent. For example, Chance Eau de Parfum is citrusy and powdery where as Chance Eau de Toilette plays up pink pepper and jasmine and Chance Eau Fraiche has notes of cedar and vetivier for a clean, almost woodsy scent.
They've done it with all their other fragrances, too. No5, Coco, Mademoiselle, etc...