Telecommunication network components configured to manage a handover of a communication session of user equipment from a packet-switched access network to a circuit-switched access network are described herein. The components may receive a handover request from user equipment, allocate circuit-switched access network resources, and request a session transfer. When the session transfer is invalid, e.g., during a pre-establishment phase of a communication session, the components may reject the transfer within a selected time and provide an invalid-handover message. Components may, in response to an invalid handover request, transmit a rejection of the session transfer and a fallback-trigger message.