A method performed by a serving gateway control plane function to manage a plurality of serving gateway user plane functions, comprising: connecting with the plurality of serving gateway user plane functions; storing serving area information of the plurality of serving gateway user plane functions; selecting a first serving gateway user plane function (404, 504) among the plurality of serving gateway user plane functions for a user equipment, according to location of the user equipment and the serving area information of the plurality of serving gateway user plane functions; sending serving area information of the first serving gateway user plane function (404, 504) to a mobility management entity; receiving, from the mobility management entity, a request for changing the first serving gateway user plane function (404, 504); reselecting a second serving gateway user plane function (805, 905, 1005) from the plurality of serving gateway user plane functions; sending serving area information of the second serving gateway user plane function (805, 905, 1005) to the mobility management entity; and deleting a session with the first serving gateway user plane function (404, 504); and any one out of: receiving, in response to that the reselection of the second serving gateway user plane function (805, 905, 1005) happens during a preparation phase of a handover procedure, an indication of not to notify a packet data network gateway (807, 906, 1007) from the mobility management entity, or receiving, in response to that the reselection of the second serving gateway user plane function (805, 905, 1005) happens during an idle mode mobility procedure, or during a completion phase of a handover procedure, an indication of to notify a packet data network gateway (807, 906, 1007) from the mobility management entity. connecting with the plurality of serving gateway user plane functions; storing serving area information of the plurality of serving gateway user plane functions; selecting a first serving gateway user plane function (404, 504) among the plurality of serving gateway user plane functions for a user equipment, according to location of the user equipment and the serving area information of the plurality of serving gateway user plane functions; sending serving area information of the first serving gateway user plane function (404, 504) to a mobility management entity; receiving, from the mobility management entity, a request for changing the first serving gateway user plane function (404, 504); reselecting a second serving gateway user plane function (805, 905, 1005) from the plurality of serving gateway user plane functions; sending serving area information of the second serving gateway user plane function (805, 905, 1005) to the mobility management entity; and deleting a session with the first serving gateway user plane function (404, 504); and any one out of: receiving, in response to that the reselection of the second serving gateway user plane function (805, 905, 1005) happens during a preparation phase of a handover procedure, an indication of not to notify a packet data network gateway (807, 906, 1007) from the mobility management entity, or receiving, in response to that the reselection of the second serving gateway user plane function (805, 905, 1005) happens during an idle mode mobility procedure, or during a completion phase of a handover procedure, an indication of to notify a packet data network gateway (807, 906, 1007) from the mobility management entity. receiving, in response to that the reselection of the second serving gateway user plane function (805, 905, 1005) happens during a preparation phase of a handover procedure, an indication of not to notify a packet data network gateway (807, 906, 1007) from the mobility management entity, or receiving, in response to that the reselection of the second serving gateway user plane function (805, 905, 1005) happens during an idle mode mobility procedure, or during a completion phase of a handover procedure, an indication of to notify a packet data network gateway (807, 906, 1007) from the mobility management entity.