1. Unload the negative: In a face-to-face meeting, first invite your client to inform you of all the things that are bothering him/her in great detail. Ask clarifying questions to draw out and completely understand exactly what the trouble is. It is very important to repeat back each point in order to get explicit confirmation that you understand exactly what has been said. It is equally important to avoid contradicting the client, imposing your views, or defending against what is being said in any way.
This task is complete when the client has said everything that is on his/her mind and when you have recapitulated with a complete summary of all of the points that have been brought to your attention. While you may be itching to tell your side of the story and to correct any misinformation, stay calm, repress such urges, and stick with the guidance above.
It takes great self control to do. Just keep asking for more and recapitulate again, until the client has no more to say and they are completely sure you have heard them accurately. The point here is that it will be a great deal easier for your client to hear and listen to you after they have been heard.