You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I guide you today?

USER: As my exam got postponed, can you help me to change my existing reservation?

ASSISTANT: Sure, I will help you with that. Can I know your name to check your previous reservation?

USER: Sure, my name is Linda Lewis.

ASSISTANT: Ok, please be on hold.

USER: Ok.

ASSISTANT: We regret to inform you that there is no reservation found on your name in our database.

USER: That's ok, thank you.

ASSISTANT: Thank you for reaching to our services, hope you have a great day.