An apparatus for a User Equipment, UE, the apparatus comprising; transceiver circuitry; and hardware processing circuitry, the hardware processing circuitry configured to: configure the transceiver circuitry to transmit, as part of a packet-switched, PS, communication session, a data message to an Evolved Node-B, eNB, of a PS network; determine that a circuit-switched, CS, communication session with a CS network is to be established; and configure the transceiver circuitry to, when the UE is operating in a failure state of the PS communication session, transmit a CS registration message to a CS base station of the CS network as part of an establishment of the CS communication session and refrain from transmission of messages to the eNB for the establishment of the CS communication session; and when the UE is operating in a non-failure state for the PS communication session, transmit a combined attachment message to the PS base station, wherein the combined attachment message includes status information for the PS communication session and further includes an indicator that the CS communication session is to be established, wherein the failure state is one of a group that includes: a first state in which the UE is de-registered from the PS network and intends to attach to the PS network; and a second state in which the UE is registered with the PS network and intends to update information related to the PS communication session. hardware processing circuitry, the hardware processing circuitry configured to: configure the transceiver circuitry to transmit, as part of a packet-switched, PS, communication session, a data message to an Evolved Node-B, eNB, of a PS network; determine that a circuit-switched, CS, communication session with a CS network is to be established; and configure the transceiver circuitry to, when the UE is operating in a failure state of the PS communication session, transmit a CS registration message to a CS base station of the CS network as part of an establishment of the CS communication session and refrain from transmission of messages to the eNB for the establishment of the CS communication session; and when the UE is operating in a non-failure state for the PS communication session, transmit a combined attachment message to the PS base station, wherein the combined attachment message includes status information for the PS communication session and further includes an indicator that the CS communication session is to be established, configure the transceiver circuitry to transmit, as part of a packet-switched, PS, communication session, a data message to an Evolved Node-B, eNB, of a PS network; determine that a circuit-switched, CS, communication session with a CS network is to be established; and configure the transceiver circuitry to, when the UE is operating in a failure state of the PS communication session, transmit a CS registration message to a CS base station of the CS network as part of an establishment of the CS communication session and refrain from transmission of messages to the eNB for the establishment of the CS communication session; and when the UE is operating in a non-failure state for the PS communication session, transmit a combined attachment message to the PS base station, wherein the combined attachment message includes status information for the PS communication session and further includes an indicator that the CS communication session is to be established, wherein the failure state is one of a group that includes: a first state in which the UE is de-registered from the PS network and intends to attach to the PS network; and a second state in which the UE is registered with the PS network and intends to update information related to the PS communication session. a first state in which the UE is de-registered from the PS network and intends to attach to the PS network; and a second state in which the UE is registered with the PS network and intends to update information related to the PS communication session.