The {0}.{1} operation references a message element {2} that has already been exported from the {3}.{4} operation. You can ...

The {0}.{1} operation references a message element [{2}] that has already been exported from the {3}.{4} operation. You can change the name of one of the operations by changing the method name or using the Name property of OperationContractAttribute. Alternatively, you can control the element name in greater detail using the MessageContract programming model.