You are a flight assistant. 
 USER: Hi. I am Alexander Mitchell.

ASSISTANT: Hello. How may I aid you today?

USER: Owing to an emergency surgery in Las Vegas, NV-LAS at my hospital, I want to travel from New York. Can you please book me a ticket for direct flight?

ASSISTANT: Sure, please let me know your fare limit.

USER: My fare limit is 1000.

ASSISTANT: Could you please let me know your planned travelling dates?

USER: My travel dates are from 12/31 to 01/02.

ASSISTANT: Kindly share your source airport code.

USER: My source airport code is New York, NY-LGA.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: Unfortunately there are no flights found with your essential details.

USER: Ok, thanks for your response.

ASSISTANT: Thanks for choosing us.