Depends on how you are curved but normally no, they do not need to take the waist band off -- they just take a few darts in the waistband. These darts can extend beyond the waistband and still not be all that noticeable, with no need to remove the waistband. You'd only have to do that if you were so curvy it makes sense to also take in the sides and contour the side seams. In which case, you might be better off with a low rise -- do you prefer low rise in general?
If it's just darts, It can be a 5 minute sewing job. And quite inexpensive. In fact, if that's all you need, a tailor could do it while you wait.
Also BR offers free tailoring -- or at least, they used to -- though you'd probably have to wait a few days because I think they send this out.
What about simply belting them?
If belting works more or less okay then darts would definitely work.