You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I address you?

USER: Could you please assist me in changing my existing reservation?

ASSISTANT: Sure, On what name the reservation was made formerly?

USER: Helen Allen.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found under your name in our data base.

USER: Ok, no worries at all. Thank you.

ASSISTANT: Thank you for opting us.