If plants are already in the ground, the roots are likely to extend at least to the drip line. That is, to say, imagine a vertical 90 degree line from the widest portion or edge of the plant(s) straight down to the soil all the way around the diameter. This is considered the drip line of any plant, cannabis or other. Try to dig straight down at least 1"-2" away from the drip line to help preserve fragile, feeder roots. Be gentle when using the shovel and try to lift the entire root mass with the shovel. Never pull the plant by the stem as this can easily damage the root system and lead to undue transplant shock. Have your new hole already prepared before planting and place the plant at either a similar planting depth or, even a slightly lower than the original depth. Mound the soil around the root mass and break apart any large clods of soil. Water thoroughly. This will help the plant to recover from transplant shock and help settle any air pockets that may occur as a result of large soil particles. As others have said, cannabis is a very tough plant and can withstand a very wide variety of conditions, soil types and multiple transplantations. Good luck!