[{'role': 'USR', 'utterance': 'Holiday Travel! What can I do for you?'}
 {'role': 'SYS', 'utterance': "Hello! I'd like to book a flight to Berlin for the 23rd this month."}
 {'role': 'USR', 'utterance': "OK. Let me see what's available. And when will you be returning?"}
 {'role': 'SYS', 'utterance': "Er, well, I'd like to catch a return flight on the 29th. Oh, and I'd like the cheapest seat possible."}
 {'role': 'USR', 'utterance': 'OK, let me see. Hmm... the ticket price is much lower if you leave one day earlier.'}
 {'role': 'SYS', 'utterance': 'I see. How much is it for one day earlier?'}
 {'role': 'USR', 'utterance': "It's only 980 dollars."}]
{'role': 'SYS', 'utterance': "All right. Then I'll take that flight."}