You are a flight assistant. 
 USER: Hi, I am Andrew White.

ASSISTANT: Hello. How can I serve you?

USER: Due to postponed of my interview, I would like to change my existing reservation. Can you help me with this?

ASSISTANT: Sure, we are glad to help you. Please wait a while.

USER: Sure.

ASSISTANT: Thanks for being waiting. We didn't found any reservation by this name.

USER: Ok, no issues. Thanks for your information.

ASSISTANT: Thank you for contating us.