You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I'm Joseph Walker. I have to change my recent reservation, as my scheduled examination dates has been postponed.

ASSISTANT: Sure, please wait for a moment to check your details.

USER: Sure.

ASSISTANT: Sorry to inform you, there is no reservation found on your name in my records.

USER: That's ok, no issues.

ASSISTANT: Thank you for choosing us, have a nice day.

USER: Anyways, thank you for the information.

ASSISTANT: Welcome.