How To Write Sick Leave Letter To Manager . How to write a sick day email. The sender should keep a copy of all communications about the leave application, and any medical letters. Sick Leave Sample Letter Collection Letter Template Collection from simpleartifact.com It is good practice to begin your email with your reason for absence. First and foremost, the letter should be convincing enough so that the manager should grant you leave without further questioning. I will let you know by tomorrow morning whether or not i can make it to work.