You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I guide you for today?

USER: I am Samuel Jackson. Please book a flight ticket on dates 12/20 and 12/22.

ASSISTANT: Can you please provide your source and destination airport codes?

USER: My airport codes are IAD and OAK.

ASSISTANT: Do you have any airline preferences?

USER: No.

ASSISTANT: Do you have any class preferences?

USER: No, I am ok with any class.

ASSISTANT: Do you have any other requirements that you are looking for?

USER: I want to return at evening.

ASSISTANT: There is a direct flight with ticket fare 200 in AA airlines in economy class. Is it ok for you?

USER:    Yes, please book a ticket for me.

ASSISTANT: Your booking is confirmed with flight number 1017. Departure time is 1:00 AM and return time is 22:00 PM.

USER: Thank you for the help.

ASSISTANT: Thank you for contacting us, have a nice day.