i need to go to broxbourne on monday train , monday , to broxbourne from cambridge .
okay , not problem . would you like to travel by train or taxi ? where are you departing from ?
{'service': 'train', 'act': 'request', 'slot_name': 'leave', 'value': '?'} {'service': 'train', 'act': 'request', 'slot_name': 'arrive', 'value': '?'}
is there a time you need to leave or arrive by ?