One way or the other, you're going to need to cut the yarn and work the second shoulder with a new strand of yarn. You can follow the directions, knit the left shoulder first, cut the yarn, place the center 17sts on a holder and then attach the new strand and follow the directions for the right shoulder.
The alternative is to knit across the left shoulder and the 17sts, then place them on a holder and work the right shoulder first. Don't worry about differences in row height or curve. The neckband or collar will probably smooth all that out.