You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I would like to change my flight reservation as my trip got postponed, can you please help me?

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

USER: I am Patrick Walker.

ASSISTANT: Ok, please wait a moment.

USER: Sure, take your own time.

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: That's ok, thank you for giving information.

ASSISTANT: Thank you for choosing us.