A data processing system which includes a data management system located in a first network, the data management system providing operations for modifying data stored by the first data management system, and a natural language processing system for processing natural language messages. The natural language processing system is located outside the first network. The system further comprises an interface application having access to the data management system adapted to: receive one or more natural language messages from a user; forward the natural language messages to the natural language processing system; receive an invocation message from the natural language processing system, the invocation message comprising operation data defining an operation to be performed at the data management system, the operation identified by the natural language processing system based on the natural language messages; and invoke the operation at the data management system based on the operation data.