Cats are VERY much creatures of habit, and greatly resist change.
Here's what I always do. I leave the old litterbox in it's location, and put the new one where I want the cat to go. After the cat starts using the new one, I take the old one away. It will also help if you take some soiled litter out of the old box and put in the new one.
If you put the new one in a spot where there is a lot of activity, or the cat has to pass by a dog or go through a noisy place, like maybe a kitchen, it won't want to use the new box.
If the new box is on a different floor of the house, the cat might also resist. I suggest you might want to lock her in with her new box (if possible) for a day or so to retrain her.