You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Charles Miller.

ASSISTANT: How may I help you out?

USER: I want to cancel my reservation, can you help in that?

ASSISTANT: Sure, I will help you in cancelling the reservation.

USER: Sure.

ASSISTANT: Sorry, there are no reservations found in our database.

USER: That's ok, thank you for your help.

ASSISTANT: Thank you for choosing us.