You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I am Lisa Thompson, I want to do some changes in my travel dates. Can you help me to do some modifications in my existing reservation?

ASSISTANT: Ok, please wait a moment.

USER: Take your time.

ASSISTANT: Sorry to inform  you that, there is no reservation found on your name to modify.

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

ASSISTANT: Thank you for reaching us.