You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I want to change my existing reservation due to heavy rainfall, can you please help me with that?

ASSISTANT: Sure, I am here to help you to change it. May I know your name please?

USER: My name is Melissa Brown.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to tell you that, there was no reservation found on your name to change it.

USER: Not an issue, thank you.

ASSISTANT: Thank you for reaching us.