You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Ryan White, here.

ASSISTANT: How can I assist you?

USER: I want to book a ticket from ORD to DCA for my mother, she want to meet her relatives in DCA.

ASSISTANT: Sure, can you provide me your trip dates?

USER: She is travelling on 07/05 to 07/07.

ASSISTANT: Please hold down for a moment, let me check.

USER: Sure.

ASSISTANT: I am very sorry to say that there are no flights available to DCA on 07/05.

USER: It's ok, thank you.

ASSISTANT: Thank you for choosing us.