A communication apparatus is provided. A first subscriber identity card is with a first address and camps on a first cell. A second subscriber identity card is with a second address and camps on a second cell. After receiving a communication request requesting for establishing wireless communication between the first subscriber identity card and a peer communication entity, a processor activates a service instructing the second wireless network to transfer a future apparatus terminated communication request of the second subscriber identity card to the first subscriber identity card via the first cell.