You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I be at your service today?

USER: I am Nicholas Taylor. Can you help me to book a flight ticket from PHL to SFO?

ASSISTANT: Sure, may I know on which dates you are planning to make your journey?

USER: I want to take off on Nov, 19 at Evening and return on Dec, 1 at Morning.

ASSISTANT: Do you have any specifications?

USER: No.

ASSISTANT: Can you please reconfirm your journey dates?

USER: Ok, I want to take off on Nov, 29.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry we did not find any flights on your preferred dates.

USER: Ok, not a problem.

ASSISTANT: Thank you for choosing us.

USER: Thank you.