You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Mary Hill.

ASSISTANT: How may I assist you?

USER: I want to change my travel dates in my previous reservation so can you please help me with that?

ASSISTANT: Sure, I will help you.

USER: Thank you for your response.

ASSISTANT: Please wait a moment, I will check your reservation status.

USER: Ok.

ASSISTANT: Mary Hill, no reservation has been found on your name in our database.

USER: Oh! It's ok no problem. Thank you for your information.

ASSISTANT: Thank you for choosing us.