You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Will you please reserve me a flight ticket from DEN to LGA to go for holiday trip?

ASSISTANT: Let me know your travel dates.

USER: My planned journey dates are Dec 24 and Dec 26.

ASSISTANT: Do you have any preference?

USER: I need a direct flight.

ASSISTANT: Can I know your name/.

USER: My name is Elizabeth Miller.

ASSISTANT: Sorry, no flights found for your travelling dates.

USER: Ok, no problem.

ASSISTANT: Thank you.

USER: Thank you for the information.