If we understand bile, it actually can't be used to pressurize the liver, or to force things out. It's not like a garden hose that is blocked. (a description I read...) Bile is a substance that is formed in the liver. But it is very thick and like sludge. In order for it to adequately serve its purpose, it must be made more fluid by the addition of bitter or sour foods and substances that help bile to flow.
The description I've just given would seem to indicate thus that it is BILE blocking the ducts rather than anything else. BUT, one must also realize that the thicker the bile, the less ability for it to enter the digestive system and break down the foods it is meant to break down. It can only digest what it surrounds. Thus the thick bile can only break down things near it, and not things far from it. It's a simple experiment. Put honey in the bottom of a glass and then add water. If you don't stir, or let it sit a while, it will still remain thick and gooey on the bottom and the water will taste mainly like water. If you stir it up, and "liquefy" it, All of the water then tastes sweet from the honey. That's exactly how bile works. In making the bile flow, we are able to digest those things that may have been stored for digestive purposes for a long time.
Bile is concentrate until we feed the body appropriately. Olive oil is a substance which helps the bile liquefy, and that is what is meant by the term "flow." It is unfortunate and misinformation to use the term as if bile were blocked. If bile were blocked, believe me, you'd be dead.