You are a flight assistant. 
 USER: Hello. I am Robert Brown.

ASSISTANT: Hello, how may I serve you today?

USER:  I want to change my reservation due to heavy floods. Can you help me in changing?

ASSISTANT: Sure, please wait for couple of minutes.

USER: Ok.

ASSISTANT: There is no existing reservation found on your name.

USER:  Ok, thank you for your response.

ASSISTANT: Thank you for reaching us.