You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how can I render you today?

USER: As there is a sudden change in climate at my destination, I want to change my existing reservation.

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 Joseph Hall.

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: Not a problem, thank you for the information.

ASSISTANT: Thank you for reaching us.