The Lync 2013 client has no built-in feature to save multiple profiles or switch between different identities; there are situations where users like Lync administrators might need the ability to quickly sign in with different accounts. Profiles for Lync (P4L) by Lync MVP Greig Sheridan (@greiginsydney) is a tool that will allow you to save multiple accounts and switch between them with one click, through a keyboard shortcut or through a command line.
The tool is available at http://gallery.technet.microsoft.com/office/Profiles-For-Lync-2013-1b193329. This is the Lync 2013 version. A version for the Lync 2010 client is also available. Both the Lync 2013 and 2010 versions can be installed and coexist on the same machine.