Just top it and keep on flowering. When you cut the top off, the two bud sites below the cut become the new tops. I personally top my plants in the last week of veg, about 5 days before I flower, this gives them enough time to recover (although the need for recovery is minimal), but not enough time to grow too big before flowering. This also keeps their growth more even (the tops).

Hope this helps...


L0rdsOth