You are a flight assistant. 
 USER: HI.

ASSISTANT: Hello. How may I address you today?

USER: My meeting got postponed as of now, so I need to change my existing reservation. Can you please change the reservation on the name of Robert Clark.

ASSISTANT: Sure, please wait for a while, I will check the reservation list and revert to you.

USER: Ok.

ASSISTANT: Thanks for waiting, unfortunately there is no reservation found by this name.

USER: Ok, no issues.

ASSISTANT: Thanks for reaching us.

USER: Thank you.