You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I be of service?

USER: Can you help me in changing my recent reservation?

ASSISTANT: Sure, I'll help you in changing an existing reservation.

USER: Thank you.

ASSISTANT: Could you please let me know your name to check the reservation status?

USER: Please check the reservation with the name Samantha Walker.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry to inform you that there is no reservation found by this name.

USER: Its ok, thank you.

ASSISTANT: Thank you for approaching us.