Shortening and lengthening the torso
Most patterns help you with this by marking a line where to cut your pattern to lengthen or shorten. Some people like to do this by eye, laying out their pattern on their fabric and making the adjustments there. I prefer to lay my patterns out on paper and adjust incrementally checking against my body as I go. It’s important to remember that if you lengthen or shorten a front piece then you will need to do the same to the reverse and vice versa to prevent an uneven make.
shortening

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Changing the neckline
There are a number of ways to alter the shape and cut of the neckline. One way to change the shape is by rotating any darts to suit your body shape but one of the most dramatic and effective ways of making a pattern work for all types of chest endowment is to raise or lower the neckline or the garment alongside adjusting dart and the torso length. You can do this by either redrafting a new shape to the neckline or by shortening the pattern at the shoulder which will move the whole garment further up the body.

neckline