You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

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

ASSISTANT: Sure, may I  know your name please?

USER: Thank you for your response, my name is Alexander Baker.

ASSISTANT: I am sorry no reservation found on your name.

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

ASSISTANT: Thank you for choosing us.