1. A method in a server coupled to a client for modifying an original data mining model for display at the client, the original data mining model maintained by the server, the method comprising: receiving a request message at the server from the client to modify the original data mining model for use at the client, wherein the request message is generated at the client and includes at least one command for modifying the original data mining model for use at the client; generating change definitions at the server from the request message to modify the original data mining model for use at the client, wherein the change definitions define only changes to the original data mining model resulting from application of the at least one command to the original data mining model at the server; storing the change definitions in a document at the server; and, transmitting the document from the server to the client, wherein the client generates a modified data mining model to replace the original data mining model at the client and for display at the client using the change definitions received from the server, whereby application of the at least one command to the original data mining model is performed at the server rather than at the client and only changes to the original data mining model resulting from the application of the at least one command to the original data mining model at the server are transmitted from the server to the client; wherein the document is a mark-up language document; and, wherein each of the original data mining model and the modified data mining model is a decision tree.