You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Melissa Martinez.

ASSISTANT: How can I help you?

USER: Can you change my reservation, which is done earlier?

ASSISTANT: Sure, I am ready to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there are no reservation found on your name.

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

ASSISTANT: Thank you for choosing us.