Abstract: An instruction is transmitted from an end user to a first customer. The instruction indicates that end user desires to receive correspondences in a first format. A message is transmitted from the first customer to a data-processing system. The data-processing system updates its memory such that first customer is now subscribed to a service for sending correspondences to the end user in the first format. Additionally, the data-processing system automatically and dynamically performs a determination to establish whether the end user is associated with other customers. Based on the determination, a message is transmitted to a second customer in an attempt to transition the second customer from one service to another service. In response, the data-processing system receives a message from the second customer and updates its memory such that second customer is now subscribed to the service for sending correspondences to the end user in the first format.