You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: Can you please help me in changing my existing reservation, as my exam got postponed. Please help me with this?

ASSISTANT: May I know your name?

USER: My name is Gary Campbell.

ASSISTANT: Sorry, no reservation found on your name to change.

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

ASSISTANT: Thank you for reaching us.