Download a letter of intent to sue (with settlement demand) to inform a defendant that you will sue if they don't pay a settlement amount. A letter of intent to sue (with settlement demand) notifies an individual that the sender intends to file a lawsuit against them.Consider the "who, what, where, and when" of your dispute. Below is a sample demand letter from a medical malpractice case that thankfully settled before a lawsuit was filed. The names and parties have been changed. Includes sender and recipient details, dispute description, settlement demand, deadline, and governing law. What is a letter of intent to sue a civil action?