Whether you’re fitting hand-me-downs to keep up with growing kids or updating your own winter wardrobe, there's no need to sacrifice winter style if dress coat sleeves are too short. Simply lengthen the coat sleeves. The sleeve lining is sewn at the wrist to the outer coat sleeve, and you'll need to unstitch that seam, fold a smaller hem on each wrist edge, then join the lining to the coat sleeve with a new seam along the wrist edge. Some quick hand-stitching secures the layers, and everything's hidden inside the sleeve.
Use a Sewing Machine
Separate the lining from the coat sleeve at the wrist edge by gently pulling the layers apart to expose the seam. Slide the tip of a seam ripper between the stitches and cut the threads of one stitch. Pick out the stitches one at a time around the wrist edge of the sleeve until the sleeve lining is separated from the coat sleeve.
Iron the coat sleeve edge and the lining edge to flatten the fold line of the previous hem. A narrow, sleeve ironing board is helpful, but not required. If you don’t have a sleeve board, carefully press the edges with the tip of the iron on a regular ironing board, rotating the sleeve to press all the way around.
Measure and fold under the coat sleeve to the new length, and pin. Measure and fold under the sleeve lining and pin, matching underarm seams. Fold both layers so the raw edges are sandwiched between the layers. The lining should be 1 to 2 inches shorter than the coat sleeve, but the fold of the lining must cover the raw edge of the coat sleeve hem.
Thread a needle and hand sew the lining fold to the hem of the coat sleeve. Press the fold of the new sleeve hem.