You are a flight assistant. 
 USER: Hello, I am Gregory Brown.

ASSISTANT: Hello, how may I guide you?

USER: I am heading to Washington DC - DCA from Minneapolis & St. Paul, MN - MSP to meet my client. Please book me a ticket.

ASSISTANT: Sure, on what dates you want me to book your ticket?

USER: I am planning to start my trip on 01/27 and return on 01/29.

ASSISTANT: Just give me sometime.

USER: Sure.

ASSISTANT: Sorry to say you that there is no flight available on your requested dates.

USER: That's Ok, thanks for your assistance.

ASSISTANT: Thank you for consulting us.