i need help finding a train . can you do that ?
user
of course . where are you traveling to ?
assistant
i would like to leave liverpool street on tuesday and arrive in cambridge .
user
we have 10 different trains on that day . do you prefer a particular time ?
assistant
i would like to arrive in cambridge by 08:45 .
user
tr6939 is your best option . it will leave at 05:39 and arrive at 07:07 . would you like to book passage on that train ?
assistant
yes , i'll need 7 tickets .
user
okay , do you need a reference number ?
assistant
yes please tyhat you for all your help