You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Kenneth Adams, want to travel from OAK to IAD.

ASSISTANT: On which dates you are willing to travel?

USER: My travelling dates are from 04/27 to 04/29.

ASSISTANT: There is no flights available.

USER: It's ok, thank you for your help.

ASSISTANT: Most welcome.