AMF NODE, NSSF NODE, TARGET SMF NODE AND METHODS PERFORMED IN A COMMUNICATIONS NETWORK

A method performed by an Access and mobility Management Function (AMF) node for allocating a target network slice instance to serve a (PDU) session for a User Equipment (UE). The AMF node receives (501), from a Network Slice Selection Function (NSSF) node, information about a decision to change an allocation of a first network slice instance that is serving the PDU session to the target network slice instance, and an identifier of the target network slice instance. The AMF node then retrieves (502), from a first Session Management Function (SMF) node of the first network slice instance, a UE context related to the UE and the PDU session. The AMF node transmits (504), towards a target SMF node of the target network slice instance, information about the retrieved UE context and Access Network (AN) tunnel information to be used for the PDU session. The AMF node receives (505), from the target SMF node, target Core Network (CN) tunnel information to be used for the PDU session. The AMF node then allocates the target network slice instance to route data flows pertaining to the PDU session by transmitting (500), towards an AN node, the target CN tunnel information to be used for the PDU session Publ.