Rotate those darts!
Darts are simply a way to remove excess fabric width at points of "fullness," such as the bust, derrière and tummy. They are typically put at points along the waist in pairs for symmetry and allow flat fabric to be manipulated into the curvy shapes women's bodies tend to take. But they don't always have to be in the same place! The importance of the dart is not where it originates, but where it points and what it removes. So, a dart that starts at the waist and points to the bust can be turned into multiple darts originating almost anywhere on the pattern piece, so long as it still removes the same amount of width as the original dart.
Take a look at the mechanics behind dart rotation. Here is my original dart that I wanted to change, with the excess cut out. When the gap is closed, the pattern piece forms a "cone" for the bust.
But, what if I want two darts, one where the original was, but one at the side seam? I cut a horizontal line from the original apex to the side seam and then rotated that piece. See? Two darts, each with half the suppression (width at seam line) as the original, so the same width was removed.
Continuing the horizontal cut to the center front, I can then rotate the other side, closing the original dart and leaving two horizontal darts.
To prove to you that the same width was removed, I cut the original dart in half and fit a half in each of the new darts.
Want a shoulder dart? Cut from the apex to the shoulder and rotate.
Neck dart, anyone?
Double french darts along the waist?
Or maybe double french darts along the side seam?
Obviously, you would want to alter the apex of the darts around the bust apex (stay one inch away from your bust apex in order for the darts to look their best), but hopefully you get the general idea of removing the same total angle from around the apex as the original dart. I plan on experimenting with dart placement for my Twist Dress, but am seriously considering the french dart, since it is partially hidden along the side.
Once you have rotated your darts, check out a great overview of how to mark and sew darts, at Sherry's post at pattern~scissors~cloth.
Happy pattern altering!