Originally Posted by
PaperPrincess
First subtract a half inch from the length and width of each piece. This removes the seam allowance.
Add (or subtract) the amount you want.
Now add the 1/2" seam allowance back to the length and width.
As long as you are dealing with squares and triangles, this will work. If you could give us additional information such as the name of the pattern, there are many of us on the board who have the program Electric Quilt that we could resize the quilt for you.