Changing desiccant bag on condenser

Hi JS, are you changing desiccant bag because your car sat around with an open/damaged A/C system? If so, then yes, definitely blow out lines. But if not, you do not have to. And if you are also replacing condenser, you should add oil. There is an image added with recommended oil amount with part replacement. I also added an article that covers different subjects in A/C. https://www.2carpros.com/articles/how-a-car-air-conditioner-works