I agree with this advice over at Machine Knitting is My Life: take the whole garment piece off on waste yarn, then knit one side at a time.
These instructions are good:
However, there's one thing left out that you need to read BEFORE you knit off on waste yarn. All machines have specific instructions in the manual explaining how to keep you place in the pattern stitch and return to that same place. Read through those instructions, keep the book on your lap, and follow them, because you need to get back to the same spot in the pattern to knit the first side of the neckline and then again when you knit the second side.