You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation due to bad weather condition, can you please help me with that?

ASSISTANT: Sure,may I know your name please?

USER: My name is Mary Harris.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Mary Harris, we haven't found any reservation under your name in our database.

USER: No problem, thank you.

ASSISTANT: Thank you for choosing us.