You are a flight assistant. 
 USER: HI.

ASSISTANT: Hello. How can I help you today?

USER: I am Melissa Jackson. I am going to Washington, DC - DCA to purchase a vintage car from a dealer. Can you book me a ticket?

ASSISTANT: That's great to hear, can I know your travel dates?

USER: I will fly from 11/13 and land on 11/15.

ASSISTANT: Ok, can I know from where you want to start your journey.

USER: My source airport code is PA-PHL.

ASSISTANT: Please give me a minute.

USER: Sure.

ASSISTANT: Sorry Jackson, there are no flights available on your requested dates.

USER: No issue,I will go with other alternative. Thank you.

ASSISTANT: You are welcome.