This question represents a signal to the director, and he must be sensitive to the message. Many actors ask the question during the rehearsal process. At the moment an actor says, "Could I talk to you about my part?" the director must become super-sensitive. He must stop doing whatever he is doing and give the actor his full attention. That sentence carries the actor's message of ultimate urgency. He must hear good news from the director at that moment, and he must have the director's full attention. If possible talk to him right away, at least to find out what the key to his discomfort is. The actor must get an answer that tells him that he is going to have an opportunity for an intimate and complete discussion with the director alone. It's better not to postpone it. The director sets a time and place where there will be no distractions. There should be no other actor within hearing and sometimes even no stage managers. The question is really not a request to talk about the part. The question is usually an indication that the actor needs to be told that he's on the right track. He cannot go a step further without the assurance that what he's doing is okay. Sometimes it is possible to say simply, "You're doing a beautiful job and I'm thrilled with the way it's going. Keep working the way you're going. It's coming nicely." The actor may be quite satisfied with this. But perhaps there is someone or something that is really troubling the actor. He must have the opportunity to receive your exclusive attention.
His difficulty may come in all sorts of disguises. It may be that one of the other actors is giving him some trouble. Perhaps he feels awkward about a certain scene or a certain kiss, or about his appearance, or about a certain emotional response. The minute you hear that question, it is very important that you give it your full and immediate attention. Don't let it slip by, because the actor could be very upset at that moment; if you don't catch him, pull him up, and resolve his difficulty then and there, he may slide into dejection or resentment. It's much more difficult to pull him out of that. If he grows morose and inefficient, it's because he didn't receive an answer when he asked, "Can I talk to you about my part."
From William Ball's A Sense of Direction.