Its called re-vegging. It can be done but I have never done it. What they say to do is leave a few small buds and leaves on the bottom of the plant and repot the plant to a bigger one. then just put back into veg. But be careful not to over feed because you have all those roots and very little plant. Thats what I have read about so take it as that and not as personal experience.
I've also read that trimming the roots can help to get the plant healthier upon reveg (I haven't done it so you may want to read into it if you're interested). Fresh soil and plenty of light are a must though.
i did it once. i did'nt repot mine though, i just flushed the soil and then fed it with veg nutes, and set the light to 24hrs fo 2 weeks and then 18/6. it grew into a nice bush