You can neck size with a FL die. Adjust your die so that it is about 1/4 turn above the shell holder. Put a small amount of lube on the mouth of the case neck (don't forget to lube the inside as you would normally) and put it through the die. Now look for the line of lube on the neck and slowly adjust your die down until that lube ring is just above the shoulder. If you decide to only neck size on a regular basis you may want to invest in a Lee Collet Neck Sizer Die.
Here is another thread that may help you:
http://thefiringline.com/forums/show...w+to+neck+size