You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: My holiday vacation has been postponed, can you please help me for changing the existing reservation?

ASSISTANT: Ok, may I know on which name you have confirmed your ticket?

USER: My previous ticket is on the name of Frank Davis.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: Sorry, Davis no reservation found on your name to change.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Most welcome.