You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Patrick Perez here.

ASSISTANT: How may I aid you?

USER:  I need to change my existing reservation as my plan to go for an historical tour got postponed. Can you please check if my reservation is active or not? If it is active, please change it.

ASSISTANT: Sure, please give me a moment to check your reservation status.

USER: Ok, sure.

ASSISTANT: Sorry, there is no reservation found on your name in our records.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for reaching us.