If you are directed by your therapist, as part of your psychotherapeutic treatment, to speak to an empty chair, which represents any persons with whom you currently have conflict, you may be engaging in therapy

The therapist is asking you to engage in Gestalt therapy. Gestalt therapy attempts to create an awareness of the here and now, both within the therapist's client and between the therapist and the client. The empty chair encourages the client's feelings thoughts and behaviors. This therapy is used to induce the client to have a better understanding of their feelings and communications.