You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,.

USER: I am Christopher Turner.

ASSISTANT: How can I aid you today?

USER: I want to change my existing reservation. Can you help me in this?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please be on hold.

USER: Ok.

ASSISTANT: Thank you for waiting.

USER: My pleasure.

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

USER: Not an issue, thank you for your information.

ASSISTANT: Thank you for reaching us.