You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: Owing to an emergency, my live concert got postponed, so I want you to change my existing reservation.

ASSISTANT: May I know your name please to check the status of your reservation?

USER: Sure, Sandra Brown here.

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation matching with your name in our portal to make changes further.

USER: Ok, no worries at all.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your information.