Final answer:
The LPN should explain that an advance directive is a legal document that outlines a person's medical treatment preferences for when they can't make decisions themselves, and can include a DNR order and appointment of a health care proxy.
Step-by-step explanation:
An advance directive is a legal document detailing a person's wishes regarding medical treatment in circumstances where they are no longer able to express informed consent, especially at the end of life. It might include a living will or a Do Not Resuscitate (DNR) order, and often also designates a health care proxy to make decisions on their behalf. In response to the client's lack of understanding, the most appropriate answer from the LPN would be to kindly explain what an advance directive is, emphasizing its importance in ensuring their medical preferences are followed, particularly in situations where they might not be able to communicate these preferences themselves.