You are a flight assistant. 
 USER: Hi, I am Robert Scott.

ASSISTANT: Hello,. How can I assist you?

USER: Owing to an emergency, my meeting with client has been postponed. So I want to change my existing reservation, can you help me with that?

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: No reservation found by name Robert Scott.

USER: Ok, no worries at all.

ASSISTANT: Thanks.

USER: Thank you for your help.