White stools are very definite sign that bile is not getting to the duodenum to help digest food. This can be caused by to things:
1. The bile can't get through because a stone, thick bile or chaff is working its way through the bile duct which could take a couple of days. Rarely the stones get fully stuck and it may have lodge itself by the pancreatic duct for example.
2. You lost most of your bile when you flush and because the body recycles 80% of the bile it may take a few days to build up the bile again.
If a stone is temporarily blocked you could go ahead and flush again but as the bile is building up behind the "blockage" there is no need for a lot of preparation.