A method for a signaling performed for supporting N2 based handover of a PDU session of a User Equipment, UE in a wireless communication system, the method comprising: receiving, by a Target-Access and Mobility Management Function, T-AMF, a create UE context request message from a Source-AMF, S-AMF, wherein the create UE context request message includes Packet Data Unit, PDU, session Identifiers, IDs, related with PDU sessions to be handed over for N2 based handover, and Single- Network Slice Selection Assistance Information, S-NSSAI, corresponding to each of the PDU session IDs; and transmitting, by the T-AMF, a PDU session update Session Management, SM, context request message to a Session Management Function, SMF, only for the PDU session ID corresponding to the S-NSSAI determined to be available in the T-AMF among the PDU session IDs, receiving, by the T-AMF, a PDU session update SM context response message in response to the PDU session update SM context request message from the SMF, wherein the PDU session update SM context response message includes a PDU session ID of which handover is accepted by the SMF, and generating, by the T-AMF, a non-accepted PDU session list including i) a PDU session ID for which handover is not accepted by the T-AMF and/or the SMF, ii) and a cause of non-acceptance for the PDU session ID for which handover is not accepted, characterized in that the cause of non-acceptance of handover includes information representing that the handover is not accepted by the T-AMF because the PDU session is related to an S-NSSAI which is determined to be not available in the T-AMF, wherein the non-accepted PDU session list generated by the T-AMF is transmitted from the T-AMF to the S-AMF. receiving, by a Target-Access and Mobility Management Function, T-AMF, a create UE context request message from a Source-AMF, S-AMF, wherein the create UE context request message includes Packet Data Unit, PDU, session Identifiers, IDs, related with PDU sessions to be handed over for N2 based handover, and Single- Network Slice Selection Assistance Information, S-NSSAI, corresponding to each of the PDU session IDs; and transmitting, by the T-AMF, a PDU session update Session Management, SM, context request message to a Session Management Function, SMF, only for the PDU session ID corresponding to the S-NSSAI determined to be available in the T-AMF among the PDU session IDs, receiving, by the T-AMF, a PDU session update SM context response message in response to the PDU session update SM context request message from the SMF, wherein the PDU session update SM context response message includes a PDU session ID of which handover is accepted by the SMF, and generating, by the T-AMF, a non-accepted PDU session list including i) a PDU session ID for which handover is not accepted by the T-AMF and/or the SMF, ii) and a cause of non-acceptance for the PDU session ID for which handover is not accepted, characterized in that the cause of non-acceptance of handover includes information representing that the handover is not accepted by the T-AMF because the PDU session is related to an S-NSSAI which is determined to be not available in the T-AMF, wherein the non-accepted PDU session list generated by the T-AMF is transmitted from the T-AMF to the S-AMF. <EOS>