Sample Letter of Authorization. A Letter of Authorization authorizes payment for medical services received over 12 months before the current month.Does the City require an authorization letter? Effective January 1st 2020 a PTAL will no longer be required for international medical graduates. 54 in the state of California any key that is marked "DO NOT DUPLICATE", or any variation, is unlawful to reproduce without a "LETTER OF AUTHORIZATION". This page presents a model letter or email you might write the school to request that your child's placement be changed. What is a Medical Exemption Request (MER)?.