You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am planning to change my departure day in my existing reservation, can you please help me out?

ASSISTANT: Sure, we are glad to help you.

USER: Thanks.

ASSISTANT: Can I have your good name?

USER: Sure, my name is Linda Harris.

ASSISTANT: Sorry to inform you that there is no active reservation on your given name.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you for contacting us.