requesting, by the first device from a second device related to a unified data management, serving access mobility management function information for a User Equipment (UE);

receiving, by the first device from the second device, i) first information informing that there is no serving access mobility management function expected for the UE and ii) second information informing maintenance of network slice-specific authentication and authorization events for the UE;

managing the network slice-specific authentication and authorization events for the UE based on the first information and the second information;

receiving, by the first device from the second device, third information regarding a new serving access mobility management function for the UE; and

transmitting, by the first device to a third device related to the new serving access mobility management function, the network slice-specific authentication and authorization events for the UE which have been managed and used for the third device to perform UE configuration update and/or a network slice-specific authentication and authorization.