You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I render you today?

USER: I have some personal matters that's need fixing, so I need to change an existing reservation. Can you please help me in that?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

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

USER: My name is Barbara Perez from Houston.

ASSISTANT: Please wait a while.

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: Ok, that's not a problem. Thanks for your information.

ASSISTANT: Thank you for choosing us.