Alexander,
Unfortunately the LicenseToken is not generally available and requires configuration to use. You would need a specific use case and you would need to speak to you account manager to get it.
However, if you are looking to reuse an existing session you could use the "SessionIDAuthenticationProperties" which would allow you to reconnect using the a session with a license. Of course, there are caveats to this... The session cannot be reused between multiple users so the session ID and the userId will need to be stored somewhere in order to properly reconnect. This will not work if dispose or disconnect has been called on the session.
The sessionId and the userId can be stored in an external resource like a database and reused without disconnecting the session.
Hope that helps.
