Place the front and back shoulder stitches onto two separate needles. Hold them in your left hand with the right sides of the knitting facing together. In your right hand, take another needle and insert the right-hand needle into the first stitch on each of the left-hand needles and knit them as one stitch. Knit the next stitch the same way. You now have two stitches on the right-hand needle. Pass the first stitch over the second stitch. Repeat until only one stitch remains on the right-hand needle. Cut the yarn and pull the tail through last stitch.