You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you today?

USER: I made an earlier reservation to attend a meeting with high officials, due to some issues it got postponed.

ASSISTANT: Sure, I will help you with that.

USER: Can you please help me to change my reservation? Thank you.

ASSISTANT: May I know your name please?

USER: My name is Joseph Clark.

ASSISTANT: I am sorry to say that there is no reservation found under your name.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for your service.