You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I support you today?

USER: I want to change my existing reservation under the name of Justin Clark. Can you help me in this?

ASSISTANT: Sure, I am here to assist you.

USER: Thank you.

ASSISTANT: Please wait a moment.

USER: Sure, take your time.

ASSISTANT: Thank you for waiting. I have checked in reservation list to change your ticket, but could not find any reservation with your name.

USER: It's alright, not an issue.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your information.