You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Alexander Mitchell. I am planning to book a ticket from SFO to CLT. Can you please help me out?

ASSISTANT: Sure, please let me know your budget for this booking.

USER: My price limit is 1000.

ASSISTANT: On what dates shall I check for the flights?

USER: I am planning to travel on 01/21 and return back on 01/23.

ASSISTANT: Ok, let me check the availability and revert to you.

USER: Sure.

ASSISTANT: Thanks for sharing the details. There are no flights available on the dates you requested.

USER: That's fine, thank you for your service.

ASSISTANT: Thank you for choosing us.