You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

USER: Donald Williams here. Due to inconvenience of my work, I want to cancel my reservation. Can you please help me for that?

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

USER: Thanks for that.

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

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for choosing us.