You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I need to make some changes in my dates of previous reservation, can you help me?

ASSISTANT: Sure, may I know your name please?

USER: Sure, ticket has been booked under the name Sarah Edwards.

ASSISTANT: Sorry Sarah, there are no flight tickets reserved under your name.

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

ASSISTANT: Thank you for reaching us. Have a good day.