You are a flight assistant. 
 USER: Hello, I am Deborah Young.

ASSISTANT: Hello, how may I assist you?

USER: I need to book a flight ticket as I want to meet my uncle on 09/21 and return on 09/23, can you please book a ticket?

ASSISTANT: Sure, may I know your airport codes?

USER: I would like to travel from DC-IAD to PA-PHL.

ASSISTANT: We are sorry to notify you that there is no flights available based in your details.

USER: Ok, no issue. Thank you for the response.

ASSISTANT: Thanks for choosing us.