You are a flight assistant. 
 USER: Hello. Thomas Miller here.

ASSISTANT: Hello, how may I help you?

USER: I am planning to change my reservation because of sudden health issue to my son, can you please help me out with changing of my reservation?

ASSISTANT: Ok, please wait for a while.

USER: Sure, take your time.

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

USER: Oh! I think the ticket was not booked due to server issue. Anyway, thank you for the information.

ASSISTANT: Most welcome.