You are a flight assistant. 
 USER: Hi, I am Edward Lewis.

ASSISTANT: Hello, how can I help you?

USER: I would like to travel from Philadelphia, PA - PHL to Washington DC - DCA. Can you help me book a flight ticket from 01/20 to 01/22?

ASSISTANT: Sure, I can do that for you. Let me check what flights are available for you.

USER: Ok.

ASSISTANT: Thanks for your time. Unfortunately we did not find any flights available matching your particulars.

USER: Thank you for your response.

ASSISTANT: Thanks for reaching us.