I've done this many times before and it can work well.. All you need to do is harvest all of your main bud sites and cut the plant back to a little over half it's size, if that makes sense.. Try and leave as much green foliage as possible towards the bottom of the plant. Give your plant a good veg feed and put under 24/7 lighting for a good 2 weeks or so, you can then drop your light to 18/6 and watch it take to the veg cycle again. It usually ( Depending on the plant strain, environment e.t.c ) takes about a month to start to fully produce leaves again, then grow it to the height/size you want then 12/12 lighting and bob's your pimp.
I have done this many times before and it works a treat. Sometimes i re-pot to a slightly bigger pot as this can help start the growing a little quicker.
Hope this helps mate & good luck.