You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I oblige you today?

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

ASSISTANT: Sure, I will help you with that. May I know your name to check your details in our database?

USER: Thank you. I am Jacob Mitchell.

ASSISTANT: Please wait a while.

USER: Ok.

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 a problem. Thank you for your information.

ASSISTANT: Thank you for choosing us.