You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Gregory Brown here.

ASSISTANT: How can I help you today?

USER: I have to visit my client office at Charlotte, can you please book a ticket from DFW to CLT?

ASSISTANT: Sure, can you share me your travelling dates?

USER: Sure, my planned departure and return travel dates are 27th and 29th of January.

ASSISTANT: Do you have any specifications?

USER: Yes, I can afford upto 500 for my ticket.

ASSISTANT: Sorry, no flights are available on your desired route.

USER: Oh! That's ok, thank you for giving the information anyways.

ASSISTANT: Thank you for reaching us.