It may surprise you to know that altering dress pants, be they men's or women's pants, is one of the most elementary tailoring jobs you can do, because most pants are designed so that they can be adjusted in this manner; almost every pair of pants has a middle back seam that makes letting out or taking in the pair quite simple. In what follows, you'll learn an easy method for letting out a pair of pants.
To begin, assemble your supplies. You'll only need a standard pair of scissors, a heavy duty needle and a ruler. Your first step is to remove the old stitching and replace with a new seam. Locate the center back seam of the pants, which normally goes up the rear all the way to the waistband. Unstitch the belt loop in this position, and then remove the stitching that was used to attach it to the pants. Open up the waistband and notice the size of the center seam. Mark your new stitch line and make sure the horizontal seam matches up. Pin into place and stitch along your markings, tapering into the seam line. Once you've finished this, pull out the original stitch line and threads. To clean up your handiwork, extend the waistband, turn the pants to the right and make sure the seams match, which they should if you've done careful work. Press the seam open and check that the top edge is even and that the seam is flat. Stitch through where the waistband meets the seat. Finally, sow the belt loop back on, doing the bottom edge first, sowing back and forth multiple times to secure it, as belt loops get lots of stress in daily use.