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 weather changing.

ASSISTANT: Sure, may I know your name please?

USER: My name is Thomas Walker.

ASSISTANT: Ok, can you please wait for a while I will get back to you.

USER: Ok.

ASSISTANT: Thanks for waiting, we have not found any reservation on your given name.

USER: Ok, no issue.

ASSISTANT: Thank you for choosing us.

USER: Thank you for your assistance.