[{'role': 'USR', 'utterance': 'I need a pan.'}
 {'role': 'SYS', 'utterance': 'Okay. Do you have a particular size in mind?'}
 {'role': 'USR', 'utterance': 'Well, the bigger the better, I think.'}
 {'role': 'SYS', 'utterance': "Look at this one. It's our biggest pan."}
 {'role': 'USR', 'utterance': "Yes, that is big enough, but it's too heavy for me."}
 {'role': 'SYS', 'utterance': 'Okay, we have the same thing in aluminum.'}
 {'role': 'USR', 'utterance': 'Oh, this is nice and light. But it has an aluminum handle.'}]
{'role': 'SYS', 'utterance': 'Try this one. Same aluminum pan, but with a heat-resistant bamboo handle.'}