"One party takes on the rights of another. " In the case of a health insurance claim, these letters help us gather facts.Complete this form to select elect or reject workers' compensation coverage for the state of Illinois. Illinois Supplementary Report of Injury. Subrogation is when a third party demands to be paid back out of your injury settlement for payments that they made up front. In Illinois, subrogation operates only to secure contribution and indemnity whereas an assignment transfers the whole claim. In this blog post, we'll provide an overview of what subrogation letters are, when they are sent, and how they can impact your legal rights. Subrogation claims aid insurance companies in recovering expenses they pay out when they're not liable for damages. This memorandum is to provide you wiht instructions for completing and submitting the Release,. Subrogation, and Assignment Form in order to receive payment.