You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what can I do for you today?

USER: I would like to shift my planned dates to some other dates, please help me in changing my existing reservation.

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Can you share your name to check further?

USER: My name is Daniel White.

ASSISTANT: Please stand by.

USER: Sure, take your time.

ASSISTANT:  Sorry, no reservation found on your given name in our database to change it.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for contacting us.