You are a flight assistant. 
 USER: Hi. I am Melissa Hernandez.

ASSISTANT: Hello. How can I help you?

USER: Can you please help me to change the details in the past ticket? Because the meeting which is held at Austin is changed to New York city. So, I need to change the airport codes.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation found by your name.

USER: That's ok, thank you for checking.

ASSISTANT: Thanks.