Wax removers are available at hardware stores. They are solvents that break down the wax and make it easier to remove. Remember that the wax has to be picked up and removed. If you apply the solvent and push a mop across the floor, you will have accomplished nothing other than spreading the wax on the floor. It must be picked up. Once the wax has been removed, lightly sand the wood with very fine sandpaper just to remove the gloss of the old varnish. This will give some bite to the floor and allow the varnish to adhere well without damaging the wood.