A method for conducting a handover of a mobile communication device from a first access network to a second access network , the method being carried out by a first computing device (AMF1) carrying out an access and mobility management function for the first access network , and the method comprising: transmitting a protocol data unit session update request to a second computing device (PGW-C+SMF, V-SMF1) wherein the second computing device carries a session management function for the second access network ; receiving, from the second computing device, an identifier of a protocol data unit session, network slice information regarding a network slice to be used by the mobile communication device to communicate on the second access network using the protocol data unit session, and session management information used for the mobile communication device to communicate on the second access network ; using the network slice information to select a network slice instance and to select a third computing device (AMF2) within the network slice instance, wherein the third computing device carries out an access and mobility management function for the second access network ; transmitting, to the third computing device, a relocation request that includes the network slice information, the identifier of the protocol data unit session, and the session management information for the mobile communication device to communicate on the second access network ; receiving, from a mobility management entity of the first access network , the mobility management context of the first access network , wherein the first access network is an evolved packet system; mapping the mobility management context of the first access network to a mobility management context of the second access network ; and transmitting the mapped mobility management context of the first access network to the third computing device. transmitting a protocol data unit session update request to a second computing device (PGW-C+SMF, V-SMF1) wherein the second computing device carries a session management function for the second access network ; receiving, from the second computing device, an identifier of a protocol data unit session, network slice information regarding a network slice to be used by the mobile communication device to communicate on the second access network using the protocol data unit session, and session management information used for the mobile communication device to communicate on the second access network ; using the network slice information to select a network slice instance and to select a third computing device (AMF2) within the network slice instance, wherein the third computing device carries out an access and mobility management function for the second access network ; transmitting, to the third computing device, a relocation request that includes the network slice information, the identifier of the protocol data unit session, and the session management information for the mobile communication device to communicate on the second access network ; receiving, from a mobility management entity of the first access network , the mobility management context of the first access network , wherein the first access network is an evolved packet system; mapping the mobility management context of the first access network to a mobility management context of the second access network ; and transmitting the mapped mobility management context of the first access network to the third computing device. <EOS>