You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: May I know your name to check your reservation status?

USER: Sure, my name is Stephen Allen.

ASSISTANT: Sorry, there is no reservation found in our database to change it.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: Welcome Stephen Allen.