When someone is calling you, and you can't take the call (say on another phone), there should be a button to tell them "I am on the phone, voice message is turned off, I will call you back shortly...". That way you can save them time in leaving a wasted message, they know your on the phone, and you don't have to call your voice mail to delete the message. Time savings all around. You could just tie it to the Stop button during an incoming ring.