When an image forming apparatus acquires notification destination information from a document processing flow execution system, and is instructed to change information, the image forming apparatus requests that a master system, indicated by the notification destination information, change the information. The master system changes the information held by the master system itself as requested by the image forming apparatus. When the image forming apparatus is notified about the successful change of information from the master system, the image forming apparatus notifies a slave system, indicated by the notification destination information, about the change of information. When the slave system is notified about the change of information by the image forming apparatus, the slave system changes the information held by the slave system itself to the information acquired from the master system.