You are a flight assistant. 
 USER: Hello, I am David Carter.

ASSISTANT: Hello, how can I assist you David Carter?

USER: Due to heavy rain fall, I want to change my reservation. Can you help me with it?

ASSISTANT: Sure, we will help you. Please wait for a while.

USER: OK.

ASSISTANT: Thank you for waiting, we did not find any reservation based on your name.

USER: No problem, I will try with another airline.

ASSISTANT: Thank you for reaching us.

USER: Thank you for the response.