You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: Myself Stephanie walker, I need to change my existing reservation. Can you please help me for changing the reservation?

ASSISTANT: Sure, I am glad to help you.

USER: Thank you.

ASSISTANT: Sorry, there is no reservation with your name to change further.

USER: Not an issue, anyhow thank you very much for your help.

ASSISTANT: You are welcome.