You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Sandra Phillips.

ASSISTANT: How can I assist you?

USER: For some issues I want to change my recent reservation, can you please help me with it?

ASSISTANT: Sure Sandra, I will help you to change your reservation. Give me a moment.

USER: Ok.

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

USER: It's ok, thank you for the help.

ASSISTANT: Welcome. Thank you for choosing us.