Lync is now Skype for Business, and is available with our Office365 subscription with a license included for every Office365 user. If Lync is presently the software installed, there is no need to upgrade to Skype for Business unless desired by end user (NOTE: Skype for Business is all that is available for any new installation or reinstallation of Office365):
1. From main window, select Settings > Personal.
2. Click the Advanced tab and change Automatic configuration to Manual configuration
3. Enter the same information for the internal and external server names:
sipdir.online.lync.com:443