Suppose you are a customer, and you are telling your photographer what you want. Instead of saying OK, what they reply is
“I am sorry, I do not know how to do that.” What will you feel? Certainly you will not consider that photographer as professional right?
Therefore, you must remember that your knowledge and the quality is the foundation of your professionalism. You aim is to try your best to cater every customer’s need. Although this can be hard sometimes, you will need to try, and therefore practice is important for a photographer.