Mayor's Office Letter Request Form. Requests must be made 10 business days prior to date the document is needed.Governor JB Pritzker is glad to assist Illinois residents in honoring their accomplishments or celebrating milestones. Requests must be made at least 30 days. Nicholas Epley finds people significantly underestimate the positive impact a letter of gratitude has on its recipient. I want to express my deepest thanks to each and every one of you who has committed to healing yourself and who have helped others in our city heal. Learn how to use an effective letter of appreciation to show your gratitude for job opportunities, job search referrals, and other kindnesses. Use a formal salutation with appropriate titles. Do not use first names. Be specific about why you are writing them and how it is positive for your business.