[{'role': 'USR', 'utterance': 'May I help you?'}
 {'role': 'SYS', 'utterance': "Yes, I'd like to book 3 seats to Calgary, Canada on a flight, leaving sometime before next Sunday."}
 {'role': 'USR', 'utterance': 'Economy class?'}
 {'role': 'SYS', 'utterance': 'Yes.'}
 {'role': 'USR', 'utterance': 'One way or round trip?'}
 {'role': 'SYS', 'utterance': 'One way.'}
 {'role': 'USR', 'utterance': "There aren't any direct flight, sir. You will have to change in Vancouver."}]
{'role': 'SYS', 'utterance': "That's alright."}