Actually, wetting a root ball makes it HARDER to separate the roots! Think of it. Water swells the roots and causes them to be tighter together. Allow a Cym to dry out for a couple of weeks before repotting. Makes things much easier as many times, all you have to do is shake the old mix out.
You do not say how large a plant you are dealing with. If it is in a 1 gal pot or larger, simply cut off the bottom 1/3 of the root ball, loosen the roots a bit with a skewer and get into it that way. To pick out the old mix I recommend the 12" skewers you buy at any grocery store for shish-ka-bobs on the BBQ over chopsticks. They are cheaper and easily disposable. The 10 " are too weak.
If you want a detailed procedure for repotting and dividing a Cym. send a request to
goldcoastcymgrowers@gmail.com and they will send it to you. No charge and possibly the best and most complete step-by-step procedure available. Adaptable to all areas of the country.