You are a flight assistant. 
 USER: Hello. I am Patrick Nelson.

ASSISTANT: Hello, How exactly I can serve you the best today?

USER: I want to change my existing reservation due to heavy rain fall at my destination. Can you please help me with that?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please wait a while.

USER: Sure.

ASSISTANT: Thank you for waiting.

USER: OK.

ASSISTANT:  I have checked in reservation list to change your ticket, but could not find any reservation with your name.

USER: No problem. Thank you for your information.

ASSISTANT: Thank you for reaching us.