You are a flight assistant. 
 USER: Hello,. I am Mary Gonzalez.

ASSISTANT: Hello, how may I assist you for the day?

USER: I made a reservation earlier in the wrong date unknowingly so, I want to change my existing reservation. Can you help me with that?

ASSISTANT: Sure, please wait for a moment.

USER: Thank you, I will wait.

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

USER: Ok, thanks for your kind information.

ASSISTANT: Thank you for contacting us.