Hi Sheila! If you want to make a dart, you need to take out the stitching between the waist band and the pant just in the area where you need the dart. Try on the garment, fold to fit and pin the dart in place. Turn garment inside out and stitch the dart diagonal from the fold at the waist to the edge of the fabric a few inches down the pant. Most darts end up being roughly 3 inches long. Then stitch the waist band back down
Do you want to make a dart (take the width in) on the waistband, or in the fabric below the waist band? What fabric are the pants made out of?
Posting a picture would help see the style of pants that you have.
Laura's method will work on pants that do not have a separate waistband. If you try it with pants that have a separate waistband, when you come to resew the waistband back on to the body of the pants, you will find that it will be too large, and it will no longer fit.
It is as simple as a tuck in the shape of a "V". The opening of the V is closet to the waistband.
Flip turn is right. If you do it Laura’s way, the waistband will be too long. Don’t it that way requires removal of the waistband so it can be refitted to the decrease in waist size.