A method for processing an outgoing call using at least one telecommunications network (30, 40) using a service platform interconnected to the at least one telecommunications network (30, 40), wherein a real call number and at least one virtual call number are allocated to each of a plurality of telephone subscribers, wherein for each telephone subscriber of the plurality of telephone subscribers at least one virtual call number and an information linking the at least one virtual number to the real call number of the respective telephone subscriber are stored on the service platform (60, 70, 72),wherein a porting code which identifies the service platform (60, 70) is assigned to a service number which is allocated to the service platform (60, 70), wherein the porting code and the service number assigned to the porting code are stored in a database which is connected to the at least one telecommunications network (30, 40); wherein the method comprises the steps of: a) entering, on the terminal of the calling telephone subscriber for whom one virtual call number and an information linking the at least one virtual number to the real call number of said calling telephone subscriber are stored at the service platform (60, 70, 72), the service number of the service platform (60, 70),; b) routing a signal message including the service number and the real call number of the calling telephone subscriber to the database and determining whether the service number entered at step a) is assigned to the porting code, c) if so, routing the signal message of step b) via the at least one telecommunications network to the service platform (60, 70) by using the porting code assigned to the service number; d) sending in response to the service number and the real call number of the calling telephone subscriber included in the signal message of step c) a request message to the terminal of the calling telephone subscriber inviting the calling telephone subscriber to enter the real call number of the called telephone subscriber; e) sending, by the terminal of the calling telephone subscriber, a signal message including the real call number of the called telephone subscriber to the service platform (60, 70); f) routing, in response to the real call number of the called telephone subscriber, the virtual call number assigned to the calling telephone subscriber to the terminal of the called telephone subscriber and establishing an outgoing call from the terminal of the calling telephone subscriber to the terminal of the called telephone subscriber using the real call number of the called telephone subscriber over the at least one telecommunications network (30, 40); and g) displaying the virtual call number of the calling telephone subscriber on the terminal of said called telephone subscriber. a) entering, on the terminal of the calling telephone subscriber for whom one virtual call number and an information linking the at least one virtual number to the real call number of said calling telephone subscriber are stored at the service platform (60, 70, 72), the service number of the service platform (60, 70),; b) routing a signal message including the service number and the real call number of the calling telephone subscriber to the database and determining whether the service number entered at step a) is assigned to the porting code, c) if so, routing the signal message of step b) via the at least one telecommunications network to the service platform (60, 70) by using the porting code assigned to the service number; d) sending in response to the service number and the real call number of the calling telephone subscriber included in the signal message of step c) a request message to the terminal of the calling telephone subscriber inviting the calling telephone subscriber to enter the real call number of the called telephone subscriber; e) sending, by the terminal of the calling telephone subscriber, a signal message including the real call number of the called telephone subscriber to the service platform (60, 70); f) routing, in response to the real call number of the called telephone subscriber, the virtual call number assigned to the calling telephone subscriber to the terminal of the called telephone subscriber and establishing an outgoing call from the terminal of the calling telephone subscriber to the terminal of the called telephone subscriber using the real call number of the called telephone subscriber over the at least one telecommunications network (30, 40); and g) displaying the virtual call number of the calling telephone subscriber on the terminal of said called telephone subscriber.