You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: Can you change the flight reservation?

ASSISTANT: Sure, but may I know your name please to change your reservation?

USER: To discuss security issues at the convention center in San Francisco an emergency meeting was arranged. But the venue has been changed. So change my flight reservation? I am Sandra Clark.

ASSISTANT: Ok, please wait for a mean while.

USER: Sure.

ASSISTANT: Sorry Sandra, there is no reservation found on your name to change your reservation.

USER: Not a problem. Thank you.

ASSISTANT: You are welcome. Have a safe journey.