Much of what is in this post is already documented in various places, but I have had to search for it enough times to warrant a concise reference. Specifically this post summarizes:
What Built-In Lync Administrator Roles Exist? How do I Determine who has Lync Administrator Access? How do I Remove or Add a Lync Administrator? What Active Directory rights are required to Install Lync? What’s New in Lync Server 2013 for Role-Based Access? What Built-In Lync Administrator Roles Exist?
Lync Server 2010 introduced role-based access control (aka RBAC) – meaning there are several Administrator roles that each have a specific set of functionality that any AD user assigned to . . . → Read More: A Lync Administrator Access Refresher