inform((_:search,day,'saturday');(_:search,destination,'cambridge');(_:search,type,'Train'))
user
am looking for a train it should leave on saturday and should go to cambridge
request((_:search,departure,?);(_:search,type,'Train'))
system
Ok , what is your departure site ?
inform((_:search,arrive_by,'9:00');(_:search,departure,'huntingdon');(_:search,destination,'Cambridge');(_:search,type,'Train'))
user
I would like to leave from Huntingdon and get to Cambridge by 9:00 pm .
request((_:search,arrive_by,?);(_:search,departure,?);(_:search,destination,?);(_:search,type,'Train'))
system
Please confirm you are leaving from Huntingdon and want to arrive at 21:00 .
user
yes , that is correct .
inform((_:booking,category,'Train');(_:booking,ref,'DDYPIE2S');(_:booking,ticket,'18.88 GBP');(_:booking,type,'Booking'))
system
Booking was successful , the total fee is 18.88 GBP payable at the station . 
 Reference number is : DDYPIE2S .
thank()
user
Thank you for all of your help ! Have a great day !
reqmore()
system
Thank you for using our services .   Do you need any further assistance ?
user
No I do n't need anything
system
You are very welcome . Please let me know if you need anything in the future .
_:search day saturday
_:search destination cambridge
_:search type Train
_:search day saturday
_:search arrive_by 9:00
_:search departure huntingdon
_:search destination Cambridge
_:search type Train
_:search day saturday
_:search arrive_by ?
_:search departure ?
_:search destination ?
_:search type Train
_:search day saturday
_:search arrive_by ?
_:search departure ?
_:search destination ?
_:search type Train
_:booking category Train
_:booking ref DDYPIE2S
_:booking ticket 18.88 GBP
_:booking type Booking
_:search day saturday
_:search arrive_by ?
_:search departure ?
_:search destination ?
_:search type Train
_:booking category Train
_:booking ref DDYPIE2S
_:booking ticket 18.88 GBP
_:booking type Booking
_:system inquired _:user