You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?>.

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

ASSISTANT: Sure, I am happy to help you and may I know your name which you have used for previous booking?

USER: My name is Ryan Jones.

ASSISTANT: Please give me a moment.

USER: Ok, I will wait.

ASSISTANT: I regret to inform you that there is no reservation found for the user name in our back end to change the ticket.

USER: Anyway, thanks for the information.

ASSISTANT: You are most welcome and thank you for approaching us.