You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Katherine White here, I want to do some changes in my dates, can you help me to to modify the ticket?

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, thank you for your information.

ASSISTANT: Thank you for reaching us.