You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Due to heavy rainfall, I would like to change my existing reservation.

ASSISTANT: Ok, I will help you with that .

USER: Thank you.

ASSISTANT: May I know your name for finding your reservation?

USER: Sure, my name is Alexander Martinez.

ASSISTANT: I am sorry, no reservation found on your name.

USER: Ok, no issue, thank you for your information.

ASSISTANT: Thank you have a nice day.