i need a train from bishops stortford to cambridge that will arrive by 12:30 . i need it for saturday .
i have found 7 trains that will get you to cambridge by 12:07 . what day would you like me to book ?
{'service': 'train', 'act': 'request', 'slot_name': 'leave', 'value': '?'}
when would you like to leave at ?