You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I am Robert Allen, want to travel from OAK to BOS. Please help me in booking my ticket.

ASSISTANT: Sure, may I know your travelling dates please?

USER: Sure, my travelling dates are from 11/26 to 11/28.

ASSISTANT: Wait a moment please.

USER: Sure.

ASSISTANT: Robert Allen, there are no flights available in your route.

USER: It's ok, thank you.

ASSISTANT: Thank you for approaching us.