w12drops,

To be helpful we need much more information. What size of pot are they in now? How are they being grown? What are the other conditions in your grow environment? What is the PH of your water and soil? What neuts are you using, how often and what amount? What type of soil? What else do you have in your soil? Are just the fan leaves turning yellow? What strain?... I think you get the point.

I have found transplanting during flowering to be very problematic. Transplanting while they are sick and flowering is a death wish for your girls. I would encourage to make sure you know what the problem is before taking any action.