You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

USER: Owing to an emergency, I want to change my existing reservation.

ASSISTANT: Surre, I'll try to help you in changing an existing reservation.

USER: Thank you.

ASSISTANT: Can I have your name to check the reservation list?

USER: Sure, Jeffrey Taylor here.

ASSISTANT: Ok, please wait a minute I will get back to you with the present status.

USER: Sure.

ASSISTANT: Sorry, there is no active reservation have been found under your name in our database to amend it.

USER: Ok, no worries at all. Thank you for your information.

ASSISTANT: Thank you for availing us.