You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Ryan Harris.

ASSISTANT: How can I guide you?

USER: I need to change my reservation as my college fest got postponed. Can you help me in changing?

ASSISTANT: Sure, We are here to help you with this change existing . Give me a minute.

USER: Sure.

ASSISTANT:  Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change  it.

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

ASSISTANT: Thank you for choosing us.