In a computer-implemented method for scheduling customer appointments in one or more service centers, wherein at least some of the customers was a mobile device having a location tracking function and a message transmission function, a central appointments scheduling system manages customer appointments, which has assigned an available time window to at least one customer. A default of a customer appointment of a first customer is recorded. The position of at least one second customer, whose available time window overlaps with the defaulted customer appointment, is detected through the use of the location tracking function of the mobile device and communication of the position to the central appointments scheduling system. The expected travel time of the second customer to the service center is calculated and, if the travel time is shorter than the time remaining up to the start time of the defaulted appointment, an offer is sent to the second customer to accept the defaulted appointment. The defaulted customer appointment is given to the second customer upon acceptance by the second customer.