They did change her. Rachelle Levefre was the original Victoria, but for Eclipse, they replaced Rachelle with Bryce Dallas Howard. She's starred in Spiderman 3, The Village, Lady in the Water, Terminator Salvation.
The reason why they replaced Rachelle was because of a "scheduling conflict". She was filming a movie called Barney's Vision, with Paul Giamatti, in Rome. Personally, they could have rearranged, but we can't really do anything about it now despite the fact that we almost had her back.