When you react to something someone says or does, you may have a problem with boundaries. If someone is able to cause havoc by doing or saying something, she is in control of you at that point and your boundaries are lost.
When you respond, you remain in control with options and choices. If you feel yourself reacting, step way and regain control of yourself so family members can't force you to do or say; and something that violates your separateness
When you have kept your boundaries, choose the best option. The difference between responding and reacting is choice. When you are reacting, they are in control. When you respond, you are.
Dr. Henry Cloud and Dr. John Townsend's Book: Boundaries.