You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Joshua Baker.

ASSISTANT: How may I guide you today?

USER: I want to travel from SEA to DEN. Can you book a flight ticket for me?

ASSISTANT: Sure, I will help you with that.

USER: I want to travel on 04/26 and 04/28.

ASSISTANT: Sure, wait for a minute.

USER: Ok.

ASSISTANT: I am sorry to say that there is no flight found.

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

ASSISTANT: Thank you for contacting us.