You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you for today?

USER: I am Catherine Mitchell. I want to book a ticket from LGA. Can you please book a ticket for me?

ASSISTANT: Yes, I will try for my best. Can I know your travelling dates?

USER: I would like to travel on 09/ 09 and return back on 09/11.

ASSISTANT: Ok, could you tell me your return airport code?

USER: My destination airport code is DEN.

ASSISTANT: Give me a moment, I will revert to you back.

USER: Sure, take your own time.

ASSISTANT: Sorry to inform you that there is no flight found on your requested criteria.

USER: That's fine. Thank you for your service.

ASSISTANT: Thank you for reaching us.