You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I render you today?

USER: I want to change my reservation due to some emergency work at Office, so please help me to change.

ASSISTANT: Sure, I will help you with that.

USER: Thank you for considering my request.

ASSISTANT: Let me know your name to check your reservation?

USER: Sure, my name is Michael Lopez.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

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: No issues, thank you.

ASSISTANT: Thank you for choosing us.