A method for transmitting or receiving a signal of a Session Management Function (SMF) in a wireless communication system comprises receiving a reject message for a message related to an activation command of a Protocol Data Unit (PDU) session, by the SMF, from a User Equipment (UE); requesting, to an AMF, an Access Management Function (AMF) information on a non-3GPP connection state modification of the UE by the SMF; receiving a message indicating that a non-3GPP connection state of the UE has been changed, by the SMF, from the AMF; and transmitting the message related to the activation command of the PDU session, which includes a new P-CSCF(Proxy-Call Session Control Function) list, by the SMF, to the UE, wherein the message indicating that the non-3GPP connection state of the UE has been changed indicates that a non-3GPP access of the UE has been changed from CM-IDLE to CM-connected.