i need a train that leaves london kings cross on friday
user
and what is your destination station ?
assistant
i need to arrive at cambridge . i want the train to leave after 17:30 .
user
there are 3 trains leaving after 17:30 on friday , by what time would you like to arrive in cambridge ?
assistant
i need to arrive by 5pm .
user
that s physically impossible . you want to leave after 17:30 which is 5:30 pm and arrive at 5 pm ? try that again please .
assistant
can i get the train id and arrival time for the first train after 17:30 on friday , going from kings cross to cambridge ?