By default, Skype for Business (Lync) maintains copies of all of your Skype for Business (Lync)-based interactions. To see a list of recent ones, do the following:
Open Skype for Business (Lync), and, above the search box, click the Conversations icon.
In the display you’ll see a chronological listing of your 100 most recent incoming and outgoing instant messages, audio and video calls, and meetings, including requests you might have missed. You can double-click any interaction to try to resume it.
You can also change, at any time, the category of information you see on the Conversation tab, by clicking either of the other two pivot filters:
Missed Shows your 100 most recent missed conversations
Calls Shows your 100 most recent incoming and outgoing audio, video, and conference calls
To see a complete listing of your interactions, if you use Outlook, click the View More in Outlook link at bottom of the Conversations window.