1. Remove the waist. There is no need to completely remove it. Just remove it from the front of the seams on both sides. First, remove the three loops at the back of the trousers.

2. Remove a side bone line from both sides, and take back pants from the side seam, depending on your waistline.

3. Mark and sew the parts to be removed.

4. Cut off the extra part after sewing, or don't cut it, in case you get fat later, you can put it back.

5. Cut the waistband at the middle waistband, sew the long waistband and sew the waistline.

6. Cut the modified interface at the waistband and sew it under the waistband, so there is no interface.