You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Deborah Hill, I want to celebrate Christmas with my family in Denver, CO - DEN. Can you aid me for booking on 12/25?

ASSISTANT: Sure, may I know your return date?

USER: Sure, I will come back on 12/27.

ASSISTANT: Could you please share your source airport?

USER: My source is Houston, TX - HOU.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, no flights found with your given details.

USER: Ok, not an issue. Thanks for your details.

ASSISTANT: Thank you for choosing us.