Instructions for completing the Third Party Letter of Authorization (LOA). Need help downloading or filling forms?Download and complete the appropriate King County construction dewatering application from the KCIW Construction dewatering webpage. The letter should begin 'Sir' or 'May it please Your Majesty'. 1. Place your name and address on the top left side of the page. Follow the standard format of a business letter. Identification document(s). In the body of the letter alternate between 'Your Majesty' and 'Your Majesty's' and 'you' and 'your'.