A third UE calls the second UE, however, the second UE is on a call with a first UE, then the call controlling device provides a voice message from said third user equipment as a background voice message to the second user equipment while keeping the call between the first user equipment and the second user equipment. The “background” in the background voice message is relative to the original call, and does not have any other special meanings. Since the original call between the first UE and the second UE is not affected, for the second UE, or a second user that uses the second UE, the voice message from the third UE is a background voice message.