To make my concern clear, Let me give you a scenario.
User A is using Skype for Business and sees an option to call for User B.
User B is not added as a delegate of User A, the question is, why does his name show on User A's Skype account?
I've checked Sefautil to see if User B is added as a delegate at the back end but to no avail.
Please see the images to see the actual screenshot, try to understand as it is written in German.