You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Sarah Brown, want to modify my ticket. Can you help me?

ASSISTANT: Sure, I will help you. Please wait a moment.

USER: Ok.

ASSISTANT: Sorry, no reservation found with your name to change the reservation.

USER: Ok, no issues. Thank you for helping me.

ASSISTANT: Thank you for reaching us.