You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Eric Roberts.

ASSISTANT: How may I help you?

USER: I am planning to visit Museum of Nature and Science at Denver, could you please help me with booking a flight ticket from SFO to DEN?

ASSISTANT: May I know your travel dates?

USER: I would like to take off on 12/17 and return on 12/19.

ASSISTANT: Sorry for this inconvenience, I could not find any flight with your requirements.

USER: That's ok, I will find an another alternate way to complete my trip. Anyways, thank you for the information.

ASSISTANT: Most welcome.