You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, Good Morning.

USER: Very Good Morning.

ASSISTANT: What can I help you?

USER: Can you please book a flight ticket on 12/25 to discuss about the business with my friend?

ASSISTANT: Sure. Could you please tell me your travelling location codes?

USER: My to and from airport location codes are LGA and LAS.

ASSISTANT: Ok, when you are returning from LAS?

USER: I want to change my dates on 11/25 and return back on 11/27.

ASSISTANT: May I know your name for documentation purpose please?

USER: Sure, my name is Eric Allen.

ASSISTANT: Sorry Eric, there are no flights available in your planned travel dates.

USER: Ok, that's fine, I request my friend to take in his car. Thank you for your help.

ASSISTANT: Thank you for reaching us.