You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I oblige you today?

USER: Can you please help me to change my existing reservation?

ASSISTANT: Sure, please share your good name.

USER: Sharon Green here.

ASSISTANT: Please stand by.

USER: Sure.

ASSISTANT: Thank you for waiting, there is no active reservation found with given name.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you.