You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I help you?

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

ASSISTANT: Sure, can you please let me know your name?

USER: Myself, Thomas Brown.

ASSISTANT: Sorry, there is no active reservation found under your name to amend.

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

ASSISTANT: Thank you for reaching us!.