A method in a communication server for enabling association of a default phone number of a mobile terminal user with either: a phone number associated with an active subscriber identity module, SIM, card, wherein the active SIM card is a SIM card currently used for communication in a mobile terminal, or a phone number associated with an active communication mode, wherein the active communication mode is one of a GSM or WLAN communication modes of the mobile terminal which is currently used for communication in the mobile terminal, the method comprising: storing a default phone number of the user; receiving and interpreting (320, 420) a communication from the mobile terminal used by the user, the communication indicating an association between an identifier of the user and either an identifier of the active SIM card of the mobile terminal or the phone number of the active communication mode of the mobile terminal; and storing (325, 425) a phone number associated with the received identifier of the active SIM card or the phone number of the active communication mode as a current phone number of the user, such that an incoming call establishment request to the default phone number of the user, from a calling phone number, causes the incoming call to be established with the current phone number of the user instead of the default phone number. a phone number associated with an active subscriber identity module, SIM, card, wherein the active SIM card is a SIM card currently used for communication in a mobile terminal, or a phone number associated with an active communication mode, wherein the active communication mode is one of a GSM or WLAN communication modes of the mobile terminal which is currently used for communication in the mobile terminal, the method comprising: storing a default phone number of the user; receiving and interpreting (320, 420) a communication from the mobile terminal used by the user, the communication indicating an association between an identifier of the user and either an identifier of the active SIM card of the mobile terminal or the phone number of the active communication mode of the mobile terminal; and storing (325, 425) a phone number associated with the received identifier of the active SIM card or the phone number of the active communication mode as a current phone number of the user, such that an incoming call establishment request to the default phone number of the user, from a calling phone number, causes the incoming call to be established with the current phone number of the user instead of the default phone number. storing a default phone number of the user; receiving and interpreting (320, 420) a communication from the mobile terminal used by the user, the communication indicating an association between an identifier of the user and either an identifier of the active SIM card of the mobile terminal or the phone number of the active communication mode of the mobile terminal; and storing (325, 425) a phone number associated with the received identifier of the active SIM card or the phone number of the active communication mode as a current phone number of the user, such that an incoming call establishment request to the default phone number of the user, from a calling phone number, causes the incoming call to be established with the current phone number of the user instead of the default phone number.