When someone is calling you, you see a pop-up notification on your screen. You can choose to answer, silence the incoming call, and then reject the call, or silence the incoming call by closing the pop-up notification window. If you silence the call, the ringtone is silenced but the caller does not see anything on their end. If you close the incoming call pop-up notification to silence an incoming call, then you do not have an option to answer or reject it any more.
If you reject the call, it causes the line to sound busy at the caller’s end and they know that you rejected the call.