Add web reference in your client application, and then consume the service.
For instance, assume that your web reference is called MyWebService and your service you want to invoke is DataServiceClient, as seen below. You can return the result in your preference container, in this example, I use a DataTable.
public static DataTable GetData(int operationID)
{
DataTable dtResult;
MyWebService.DataServiceClient client = new MyWebService.DataServiceClient();
dtResult = client.GetData(operationID);
client.Close();
return dtResult;
}