access Lync / Skype for Business conversation in C#

I'm facing a use case, where it shall be possible to take over a Lync/Skype for Business Conversation into my Software. The help desk user was contacted by a customer via Skype for Business and now needs to create a ticket from that conversation. Only the chat-conversation is needed, no voip conversations or so.

I could not find any documentation about how to start any Actions out of a Skype for Business conversation window.

I'm sure, somebody solved that before.

Solution

Note that:

"Skype for Business" is basically a rebranded Lync, so Shane's advice about the "Lync Client SDK" is correct.
"Skype" != "Skype for Business". It's like java and javascript, totally different, just similar names for branding.
Persistent Chat means "chat rooms that remain". Skype for Business has regular IM chat and its much less used "Persistent Chat".
tel.red can do this for you if you pay them.